Sprite Loom — Offline PNG Atlas Workshop

From loose sprites to one clean sheet.

Sprite Loom is a small offline workshop for static PNG atlases. Unzip it, open index.html in a desktop browser, and work with files on your own device.

Included in the $1 download

• Import up to 128 static PNGs, trim transparent margins and retain original-size offsets.
• Set transparent padding and edge-pixel extrusion independently.
• Pack without rotation, inspect individual frames and export PNG, JSON and CSV.
• Readable HTML/CSS/JavaScript source, a guide, license and 16 example sprites with an exported sample atlas.

Try the free sample first

The sample atlas inspector lets you inspect frame coordinates and reconstruct the included sprites. It does not import or pack your own art. The paid download contains the complete tool.

Limits, stated plainly

Static PNG only; no APNG, SVG, GIF or animation input. Maximum input dimensions 2,048 × 2,048 px per image, 8 MB per file, 64 MB total and 32 megapixels decoded. Maximum output atlas 4,096 × 4,096 px. Greedy packing is not guaranteed optimal. No rotation, multipage atlases or engine plugin. JSON uses the documented sprite-loom/1 schema; adapt it to your engine.

Imported images live in memory only. Keep your originals and export before reloading. Tested in desktop Chrome; other browsers are not verified.

Commercial work and privacy

You retain your rights in your input art and exports. Personal and commercial project use is allowed under the included license. Tool/source resale is not allowed. No network calls, telemetry, external fonts or third-party libraries are used by the app.

AI disclosure

Code, example geometry and documentation were created with generative AI assistance. No stock art or third-party icon packs are bundled.