Schema Markup
alirezarezvani/claude-skills
When the user wants to implement, audit, or validate structured data (schema markup) on their website.
A skill your agent uses when reviewing image assets, markup, and CDN or build transforms related to Use progressive JPEG encoding.
MITAuto-check passed
Install Progressive Jpeg
$ npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install thedaviddias/Front-End-Checklist progressive-jpeg --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/progressive-jpeg .claude/skills/progressive-jpeg && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "progressive-jpeg" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/progressive-jpeg into .claude/skills/progressive-jpeg/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "progressive-jpeg", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/progressive-jpegType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install thedaviddias/Front-End-Checklist progressive-jpeg --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/progressive-jpeg .agents/skills/progressive-jpeg && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "progressive-jpeg" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/progressive-jpeg into .agents/skills/progressive-jpeg/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "progressive-jpeg", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install thedaviddias/Front-End-Checklist progressive-jpeg --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/progressive-jpeg .cursor/skills/progressive-jpeg && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "progressive-jpeg" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/progressive-jpeg into .cursor/skills/progressive-jpeg/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "progressive-jpeg", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/thedaviddias/Front-End-Checklist.git --path skills/progressive-jpeg--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install thedaviddias/Front-End-Checklist progressive-jpeg --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/progressive-jpeg .gemini/skills/progressive-jpeg && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "progressive-jpeg" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/progressive-jpeg into .gemini/skills/progressive-jpeg/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "progressive-jpeg", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install thedaviddias/Front-End-Checklist progressive-jpegInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/progressive-jpeg .github/skills/progressive-jpeg && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "progressive-jpeg" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/progressive-jpeg into .github/skills/progressive-jpeg/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "progressive-jpeg", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install thedaviddias/Front-End-Checklist progressive-jpeg --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/progressive-jpeg .opencode/skills/progressive-jpeg && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "progressive-jpeg" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/progressive-jpeg into .opencode/skills/progressive-jpeg/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "progressive-jpeg", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
progressive-jpeg- GitHub stars
- 74k
- Token cost
- ~426 tokens
- SKILL.md length
- 159 words
- Files
- 2 (incl. references)
- Skills in repo
- 390
- Repo updated
- First seen
- Licence
- MIT
At a glance
A skill your agent uses when reviewing image assets, markup, and CDN or build transforms related to Use progressive JPEG encoding.
- Reviewing image assets
- SKILL.md covers Quick Reference, Check, Fix and Explain, plus 1 more section
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Build transforms related to Use progressive JPEG encoding
What it does
Progressive Jpeg is an agent skill from thedaviddias/Front-End-Checklist. Use when reviewing image assets, markup, and CDN or build transforms related to Use progressive JPEG encoding. Check encoded size, rendered size, loading strategy, and above-the-fold impact together.
Its SKILL.md is about 430 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/rule.md`).
The repository describes itself as: 🗂 The essential checklist for modern web development, for humans and AI agents. The licence is MIT.
When your agent uses it
- Reviewing image assets
- Build transforms related to Use progressive JPEG encoding
Example prompts
- “/progressive-jpeg”
What it can do on your machine
Read from SKILL.md and the folder at commit e8d14d0. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
frontendchecklist.io
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Progressive Jpeg loads about 426 tokens when it runs, and up to ~1.5k if it reads all its reference files. Until then it costs about 54 tokens; SKILL.md has 159 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from thedaviddias/Front-End-Checklist at commit e8d14d0, republished under its MIT licence (© thedaviddias). 159 words, ~426 tokens.
Download SKILL.mdSave it as
.claude/skills/progressive-jpeg/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- progressive-jpeg
- description
- Use when reviewing image assets, markup, and CDN or build transforms related to Use progressive JPEG encoding. Check encoded size, rendered size, loading strategy, and above-the-fold impact together.
- metadata.category
- images
- metadata.priority
- low
- metadata.difficulty
- beginner
- metadata.estimatedTime
- 10
- metadata.source
- frontendchecklist.io
- metadata.url
- https://frontendchecklist.io/rules/images/progressive-jpeg
Use progressive JPEG encoding
Progressive JPEGs display a low-quality preview immediately rather than loading line-by-line—users see something faster, improving perceived performance even if total load time is similar.
Quick Reference
- Progressive JPEGs show blurry preview immediately, then sharpen
- Better perceived performance than baseline JPEGs that load top-to-bottom
- Similar file size to baseline JPEG (sometimes slightly smaller)
- Less relevant with modern formats (WebP, AVIF) but still useful for fallbacks
Check
Check if JPEG images are saved in progressive format for better perceived performance.
Fix
Convert baseline JPEGs to progressive format for improved loading experience.
Explain
Explain how progressive JPEGs show a low-quality preview that improves perceived performance.
Code Review
Review image assets, markup, and delivery configuration related to Use progressive JPEG encoding. Flag exact files or components where format choice, sizing, or loading behavior violates the rule, and describe how to confirm the fix in DevTools.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/images/progressive-jpeg
© thedaviddias, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 1 other file (references) in skills/progressive-jpeg of thedaviddias/Front-End-Checklist.
- SKILL.md
- references/rule.md
Open the folder on GitHubat commit e8d14d0
Compare with similar skills
Progressive Jpeg next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Progressive Jpeg this skillthedaviddias/Front-End-Checklist | 74k | — | ~426 | Automated safety check: Pass | MIT | |
| Schema Markupalirezarezvani/claude-skills | 28k | 1 repos | ~2.9k | Automated safety check: Pass | MIT | |
| Progressive Buildingn8n-io/n8n | 207k | — | ~1.6k | Automated safety check: Pass | Custom licence | |
| Schema Markup Generatorsickn33/agentic-awesome-skills | 47k | 1 repos | ~2.1k | Automated safety check: Pass | MIT | |
| Remotion Markupremotion-dev/remotion | 63k | 2 repos | ~4.6k | Automated safety check: Pass | Custom licence | |
| Progressive Web Appdavila7/claude-code-templates | 33k | 3 repos | ~3.1k | Automated safety check: Pass | MIT |
Similar skills
- Official
Progressive Building
n8n-io/n8n
Load before build-workflow and before scoping or planning new workflows and feature additions, including requests spanning multiple workflows.
Schema Markup Generator
sickn33/agentic-awesome-skills
Generate and implement JSON-LD structured data for web apps, blogs, FAQs, and SaaS sites.
- Official
Remotion Markup
remotion-dev/remotion
Content, animation and effects best practices. An agent skill from remotion-dev/remotion.
Progressive Web App
davila7/claude-code-templates
Build Progressive Web Apps (PWAs) with offline support, installability, and caching strategies.
Cdn Setup
sickn33/agentic-awesome-skills
Configure CDNs for content delivery. An agent skill from sickn33/agentic-awesome-skills.
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Audits article and blog pages for visible publish dates, Article JSON-LD with datePublished and dateModified, and Open Graph time tags, then fixes what is missing.
FAQPage Schema Markup
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Adds, checks and fixes FAQPage JSON-LD on pages with visible question-and-answer sections so it matches what readers see and can qualify for rich results.
Favicon Audit and Setup
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Checks that a site's favicon is linked, reachable and large enough for Google search results, and sets up ICO, SVG and Apple touch icon files when they are missing.
Content Freshness Signals
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Audits article pages for freshness signals, covering the Last-Modified header, Article JSON-LD dateModified and a visible last-updated date, and fixes mismatches.
Geo Meta Tags Audit
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Audits and fixes geo.region, geo.placename and geo.position meta tags on regional pages, noting where they help (Bing) and where they do not (Google).
Improve a Front-End Checklist Rule
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Scores and rewrites a Front-End Checklist rule MDX file against a scored quality rubric, replacing generic stub prompts with specific, actionable ones.
Questions about Progressive Jpeg
What does Progressive Jpeg do?
A skill your agent uses when reviewing image assets, markup, and CDN or build transforms related to Use progressive JPEG encoding. Progressive Jpeg is an agent skill from thedaviddias/Front-End-Checklist. Use when reviewing image assets, markup, and CDN or build transforms related to Use progressive JPEG encoding.
When should I use Progressive Jpeg?
Progressive Jpeg fits situations like: reviewing image assets; build transforms related to Use progressive JPEG encoding.
How do I install Progressive Jpeg in Claude Code?
Run `npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a claude-code`. Or copy the skill folder (skills/progressive-jpeg in thedaviddias/Front-End-Checklist) into .claude/skills/progressive-jpeg in your project. Claude Code loads it when a task matches its description.
How do I install Progressive Jpeg in Codex?
Run `npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a codex`. Or copy the skill folder (skills/progressive-jpeg in thedaviddias/Front-End-Checklist) into .agents/skills/progressive-jpeg in your project. Codex loads it when a task matches its description.
Can I use Progressive Jpeg in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add thedaviddias/Front-End-Checklist --skill progressive-jpeg -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/progressive-jpeg, .gemini/skills/progressive-jpeg, .github/skills/progressive-jpeg and .opencode/skills/progressive-jpeg in your project.
What does Progressive Jpeg need to run?
SKILL.md names no scripts, command-line tools or credentials: Progressive Jpeg is instructions for the agent only.
Does Progressive Jpeg access the network?
SKILL.md names 1 domain. As links in the text: frontendchecklist.io. This is read from the text; nothing was executed.
Is Progressive Jpeg safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Progressive Jpeg use?
Progressive Jpeg is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Progressive Jpeg use?
About 426 tokens (SKILL.md is roughly 1.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1.1k tokens, read only when the agent opens those files.
What are the alternatives to Progressive Jpeg?
Skills that share tags, products or a category with Progressive Jpeg: Schema Markup (alirezarezvani/claude-skills, 28k stars), Progressive Building (n8n-io/n8n, 207k stars), Schema Markup Generator (sickn33/agentic-awesome-skills, 47k stars) and Remotion Markup (remotion-dev/remotion, 63k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Progressive Jpeg?
thedaviddias (a GitHub user) maintains it in thedaviddias/Front-End-Checklist, which has 74,421 GitHub stars. The repository holds 390 skills in this directory. The repository was last updated on October 6, 2026.
Source: thedaviddias/Front-End-Checklist on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.