How do I install the Compress Assets skill?

Run npx skillmds@latest add forge-space/compress-assets in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

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Is Compress Assets free to use?

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Who published Compress Assets?

Forge-Space (@forge-space) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Compress Assets by forge-space — Agent Skill

Name: Compress Assets
Author: Forge-Space

Compress Assets

Losslessly compress PNG and SVG assets in place and generate .webp siblings for every raster image. Use when the user asks to "compress assets", "optimize images", "shrink the assets folder", or "convert to webp". Runs a deterministic pipeline via oxipng + svgo + cwebp + ImageMagick.

Forge-Space 7c26ea3 3.0 KB Updated Sep 17, 2026

File contents

compress-assets

Shrink a repo's image assets without visible quality loss and emit modern .webp siblings so <picture> tags can serve them to supporting browsers.

When to use

"compress the assets", "optimize images", "convert to webp", "shrink the repo"
Before a release when the repo has grown over time
After dropping in designer-provided PNG/SVG/JPG that weren't pre-optimized

Pipeline

Per file, by extension:

Source	Tool	Flags	Output
`*.png`	`oxipng`	`-o max --strip safe`	in-place (lossless, reverts if output grows)
`*.png`	`cwebp`	`-q 85 -m 6 -mt`	`<name>.webp` (kept only if smaller than source)
`*.svg`	`svgo`	`--multipass`	in-place
`.jpg` / `.jpeg`	`magick`	`-strip -interlace Plane -sampling-factor 4:2:0 -quality 85`	in-place (kept only if smaller)
`.jpg` / `.jpeg`	`cwebp`	`-q 85 -m 6 -mt`	`<name>.webp` (kept only if smaller than source)
`.webp`, `.gif`, `*.pbm`	—	kept as-is	—
`.DS_Store`	`rm`	—	deleted

Preconditions

brew install oxipng svgo pngquant webp imagemagick

Verify: which oxipng svgo cwebp magick.

Usage

Run the bundled script (ship one copy per repo at scripts/compress-assets.sh):

./scripts/compress-assets.sh assets   # default dir is "assets"

The script prints before/after bytes per file and a summary block with per-type totals and total WEBP bytes added.

Consuming the .webp siblings

Replace <img src="foo.png"> with a <picture> fallback so PNG stays intact:

<picture>
  <source srcset="assets/foo.webp" type="image/webp" />
  <img src="assets/foo.png" alt="..." width="720" />
</picture>

GitHub's README renderer supports this — modern browsers get webp, everyone else falls back to the already-optimized PNG.

Don'ts

Do not run pngquant in the default pipeline — it's lossy and not needed when oxipng gets 20–40 % for free. Only enable it if oxipng's output still exceeds a size budget.
Do not delete original PNG/JPG files when emitting webp — keep both so <picture> fallback works.
Do not recompress animated GIFs with this pipeline; they need gif2webp or ffmpeg instead.
Do not run on node_modules/, build output, or committed binary bitmaps (.pbm) meant for pipelines.

Expected gains (indicative)

PNG: 20–45 % size reduction (oxipng strip + max level)
SVG: 5–30 % (whitespace + default plugins)
JPG: 25–50 % when source was saved unoptimized
WEBP siblings: 60–90 % smaller than source PNG/JPG

optimize-context — unrelated, for token budget not byte budget
dev-assets-sync — syncs Claude config assets, not repo images

---name: compress-assetsdescription: Losslessly compress PNG and SVG assets in place and generate .webp siblings for every raster image. Use when the user asks to "compress assets", "optimize images", "shrink the assets folder", or "convert to webp". Runs a deterministic pipeline via oxipng + svgo + cwebp + ImageMagick.---# compress-assetsShrink a repo's image assets without visible quality loss and emit modern `.webp` siblings so `<picture>` tags can serve them to supporting browsers.## When to use- "compress the assets", "optimize images", "convert to webp", "shrink the repo"- Before a release when the repo has grown over time- After dropping in designer-provided PNG/SVG/JPG that weren't pre-optimized## PipelinePer file, by extension:| Source | Tool | Flags | Output ||---|---|---|---|| `*.png` | `oxipng` | `-o max --strip safe` | in-place (lossless, reverts if output grows) || `*.png` | `cwebp` | `-q 85 -m 6 -mt` | `<name>.webp` (kept only if smaller than source) || `*.svg` | `svgo` | `--multipass` | in-place || `*.jpg` / `*.jpeg` | `magick` | `-strip -interlace Plane -sampling-factor 4:2:0 -quality 85` | in-place (kept only if smaller) || `*.jpg` / `*.jpeg` | `cwebp` | `-q 85 -m 6 -mt` | `<name>.webp` (kept only if smaller than source) || `*.webp`, `*.gif`, `*.pbm` | — | kept as-is | — || `.DS_Store` | `rm` | — | deleted |## Preconditions```bashbrew install oxipng svgo pngquant webp imagemagick```Verify: `which oxipng svgo cwebp magick`.## UsageRun the bundled script (ship one copy per repo at `scripts/compress-assets.sh`):```bash./scripts/compress-assets.sh assets # default dir is "assets"```The script prints before/after bytes per file and a summary block with per-type totals and total WEBP bytes added.## Consuming the .webp siblingsReplace `<img src="foo.png">` with a `<picture>` fallback so PNG stays intact:```html<picture> <source srcset="assets/foo.webp" type="image/webp" /> <img src="assets/foo.png" alt="..." width="720" /></picture>```GitHub's README renderer supports this — modern browsers get webp, everyone else falls back to the already-optimized PNG.## Don'ts- Do **not** run `pngquant` in the default pipeline — it's lossy and not needed when oxipng gets 20–40 % for free. Only enable it if oxipng's output still exceeds a size budget.- Do **not** delete original PNG/JPG files when emitting webp — keep both so `<picture>` fallback works.- Do **not** recompress animated GIFs with this pipeline; they need `gif2webp` or `ffmpeg` instead.- Do **not** run on `node_modules/`, build output, or committed binary bitmaps (`.pbm`) meant for pipelines.## Expected gains (indicative)- PNG: 20–45 % size reduction (oxipng strip + max level)- SVG: 5–30 % (whitespace + default plugins)- JPG: 25–50 % when source was saved unoptimized- WEBP siblings: 60–90 % smaller than source PNG/JPG## Related- `optimize-context` — unrelated, for token budget not byte budget- `dev-assets-sync` — syncs Claude config assets, not repo images

Frequently asked questions