Sprite Sheet Generator

Every time a web page or game loads a separate image file for each icon, button state or animation frame, the browser or engine sends a separate HTTP request. For a set of thirty sprites, that is thirty requests — thirty round-trips of latency before anything renders. Combining them all into a single sprite sheet (also called a texture atlas) cuts that to one request, and the JSON frame map tells the engine exactly where each sprite lives in the combined image so it can draw only that region when needed.

Web developers use sprite sheets to deliver icon sets or UI elements in one optimized PNG, referencing each icon with a CSS background-position offset. Game developers pack animation frames and tile sets into atlases that the GPU can load as a single texture, dramatically reducing draw calls. The Sprite Sheet Generator packs your individual PNG, JPG or WebP images into rows under a maximum sheet width, with configurable padding, scale, and pack order. Drag rows in the sprite list to reorder them before packing, and if two files share a name, the second is automatically renamed (name_2, name_3, …) so nothing silently gets dropped from the export.

Two toggles handle the prep work that used to be manual: trimming crops each sprite to its opaque pixels before packing for a tighter sheet, and rounding the sheet size up to the next power of two matches what GPUs expect in a game engine. Packing itself uses a shelf algorithm — sprites are placed left to right, wrapping to a new row when the next one would exceed the max width — with an optional tallest-first ordering that reduces wasted space compared to plain upload order. It is not the globally optimal packing algorithm (that would be a bin-packing NP-hard problem), but it is fast, predictable, and handles the common case well.

The tool exports three files: the packed PNG atlas, a JSON frame map — either a simple flat format or one shaped to match TexturePacker's Hash JSON (compatible with Phaser and PixiJS atlas loaders) — and a CSS file with one class per sprite, ready to reference the PNG with a background-position offset. All processing happens on a canvas in your browser with no upload.

If you have searched for a "sprite atlas generator" or a "sprite map maker" and landed here, you are in the right place — these names all describe the same output: many small images packed into one combined image with a data file recording where each piece sits. The term you use mostly depends on your community.

Web developers usually say "sprite sheet." Game engine documentation, from Unity to Godot, tends to say "texture atlas." Some 2D toolkits and frameworks call it a "sprite map." Whichever term you know it by, this generator produces exactly that: a single packed PNG plus a JSON frame map, so it works as a sprite sheet, a texture atlas, and a sprite map all at once.

Packing the images is the easy part — a sheet is only as useful as the source files you feed it and the settings you pack them with. A few habits make the exported atlas far easier to work with in code.