The short answer for source art
Save your source game assets as PNG. Sprites, character animations, tilesets, UI and most 2D textures all rely on two things PNG guarantees: lossless pixels that never degrade no matter how many times you re-export, and a full alpha channel for clean transparent edges. The table maps the common asset types to a sensible source format.
| Asset | Source format |
|---|---|
| Sprites & animations | PNG |
| UI / HUD elements | PNG |
| Tilesets & atlases | PNG |
| Large opaque backgrounds | JPG or WebP (no alpha needed) |
| Web delivery / download size | WebP (from PNG source) |
Why PNG wins for sprites, UI and textures
Pixel art and game UI live or die on sharp, exact edges. PNG's lossless compression means a one-pixel outline stays one crisp pixel wide and the colours never shift, unlike a lossy format that would smear them. Its eight-bit alpha channel also gives you soft anti- aliased edges and partial transparency — essential for glows, shadows and feathered sprites that must composite cleanly over any background. For a deeper look at how that compression stays lossless, see how PNG compression works.
Why PNG dominates 2D sprite sheets
A sprite sheet packs many frames into one large image so the GPU can draw them in fewer batches. That image is full of transparent gaps between frames and razor-sharp boundaries — precisely the content a lossy format ruins, because JPG bleeds colour across the empty space and creates halo artefacts around each sprite. PNG keeps every frame isolated and pixel-perfect, which is why nearly every atlas packer and 2D engine treats PNG as the default sheet format. When sheets grow large, you can trim the file with a PNG compressor without touching the pixels.
When JPG or WebP actually fit
Not every asset needs PNG. A full-screen painted background, a distant skybox or a photographic surface that is fully opaque and never needs transparency is a fine candidate for JPG, where mild compression is invisible at playing distance and the file is a fraction of the size. WebP is the modern middle ground: it supports transparency and compresses smaller than PNG, making it excellent for web-delivered games and for shrinking the download. A practical workflow is to author everything in PNG and convert only the heavy backgrounds at packaging time. Sizes still need to match your atlas grid, so resizing a PNG to power-of-two dimensions before export keeps the import clean.
Engine and runtime notes
It helps to separate source format from runtime format. In Unity and Godot you import PNGs, and the engine re-compresses them on build into GPU formats — DXT and BCn on desktop, ETC2 or ASTC on mobile — that the graphics card reads directly. You never hand-author those; they are an export setting. Power-of-two dimensions (512, 1024, 2048) let the engine generate mipmaps and apply that compression most efficiently, and they avoid wasted texture memory. So keep crisp PNG masters, mind your dimensions, and let the engine decide the runtime encoding. Ready to prepare files? Browse the full set of PNG tools.
Frequently asked questions
- What format should I save my source sprites in?
- PNG. It is lossless and supports a full alpha channel, so transparent edges and crisp pixel art survive every save. Keep your authoring files (PSD, Aseprite, Krita) too, but export the shipped sprites as PNG.
- Is it ever fine to use JPG in a game?
- Yes, for large fully-opaque images such as a sky box, a painted background or a photographic decal where no transparency is needed and a little compression loss is invisible. Never use JPG for sprites, UI or anything with hard edges or alpha.
- Should I use WebP for game textures?
- WebP can shrink download size noticeably and supports transparency, which is handy for web games and asset delivery. Many engines still import PNG most reliably, so a common pattern is to author in PNG and convert to WebP only for distribution.
- Do my textures need to be power-of-two sizes?
- For tiling, mipmapping and older GPU compression, power-of-two dimensions (256, 512, 1024, 2048) are safest and let the engine compress most efficiently. Modern engines tolerate non-power-of-two textures, but UI atlases and 3D textures still benefit from sticking to them.
- What about DXT, ETC and other compressed formats?
- Those are GPU runtime formats the engine creates during import — you do not author in them. You ship PNG source art and the engine compresses it to DXT/BCn on desktop or ETC/ASTC on mobile when it builds, so it is a separate concern from your source format.