Spritesheet Generator packs PNG, JPG, GIF, and WebP images into sprite sheets, splits existing sheets back into frames, and previews the animation. A plain PNG grid works in any engine that slices by cell size, Unity and GameMaker included. Atlas files are written for Phaser and PixiJS (JSON), Aseprite (JSON), Godot (.tres), Tiled (.tsj), Starling and Sparrow (XML), and CSS. Images are processed in your browser and are only uploaded if you publish to the gallery or save a project online.