Which Image Formats Work for Codex Pets? JPG vs PNG vs WebP

What Codex actually loads

The short answer to the codex pet image format question: Codex reads one file, spritesheet.webp, from a subfolder of ~/.codex/pets. That is it. The spritesheet is a WebP grid of animation frames, and pet.json tells Codex how to slice it. Your source photo can be JPG, PNG or WebP, but the pet that ends up on your desktop is always WebP.

JPG vs PNG vs WebP for pixel pets

JPG is the format nobody thinks about until it bites you. It is lossy, and lossy compression blurs the sharp edges that pixel art depends on. At low compression settings the difference is visible, especially on outlines. PNG is lossless, which makes it the safest source format: hard edges stay hard, and transparency works cleanly. WebP sits in the middle as a source, but it is also the only output format that matters here, since that is what Codex loads.

• JPG: fine for photos, worst for pixel art sources; compression smears edges
• PNG: lossless, keeps hard pixel edges, supports transparency; best source format
• WebP: modern, smaller files, and the required output format for spritesheets

What happens if you upload a JPG or PNG

Generators like PetGen accept JPG, PNG and WebP as input, convert the image into a pixel-art grid, and export the ZIP with spritesheet.webp plus pet.json. You never deal with the WebP conversion by hand. The practical takeaway: pick the cleanest source you have, PNG preferred, and let the generator do the format work.

The best format for pixel pet sources

If you are choosing a source image, the best format for pixel pet work is PNG, for three reasons: lossless edges, transparency support, and predictable file size. A 1024x1024 PNG stays well under typical 10MB upload caps. JPG only makes sense when the source is a photo and PNG is unavailable. WebP as a source is fine but unnecessary, since it will be re-encoded anyway.

Upload size and quality trade-offs

On the codex pet upload size front, keep it under 10MB. If your image exceeds that, resize to 1024px or 2048px on the long side before uploading. Compression at that point costs almost nothing, because pixel art is simple geometry; a 2048px PNG of a cartoon character is typically a few hundred KB, nowhere near the cap.

Frequently asked questions

• Do I need to convert my image to WebP before uploading? No. Upload JPG, PNG or WebP; the generator handles the conversion to spritesheet.webp.
• Does Codex support GIF pets? Not as spritesheets. If your animation comes as a GIF, convert frames to a WebP grid first, or use a generator that does it for you.
• Can a spritesheet be PNG instead of WebP? Some community loaders accept PNG, but stock Codex expects spritesheet.webp. Keep the standard format to avoid load failures.
• Will a large upload slow down the generator? Slightly. Above 2048px the benefit is marginal for pixel art; keep sources reasonably sized for faster results.