What works best
Clean line art, cel-shaded frames, logos, sprites and UI textures upscale very well: edges stay crisp and flat regions stay flat instead of turning into noise. Heavily compressed JPEG screenshots also improve, because the model was trained on realistic compression artifacts.
Transparent PNGs keep their transparency. The alpha channel is upscaled separately and re-applied, so stickers, emotes and cut-out characters come back with clean edges rather than a black or white halo.
Where to expect limits
The general model is not the dedicated anime variant of Real-ESRGAN, so very soft, painterly styles can come out slightly sharper than the original intent. Faces in photographs may keep some softness, since there is no separate face-restoration pass. Tiny pixel art (under 64 pixels) is better served by nearest-neighbor scaling if you want the blocks preserved exactly.
Sizes and formats
Input up to about 6 megapixels on desktop and 2 megapixels on phones (larger images are reduced to fit first); output is 4× the width and height as a lossless PNG, with JPEG and WebP as options. 800×600 becomes 3200×2400.
Accepted inputs: PNG, JPEG, WebP, GIF, BMP, AVIF, HEIC (iPhone photos) and TIFF scans. Nothing is uploaded to decode them: the HEIC and TIFF decoders load into the page on demand.
Questions, answered
Is this the anime version of Real-ESRGAN?
No. It runs realesr-general-x4v3, the compact general-purpose model, which handles line art and flat color well. The dedicated anime model is available in desktop tools such as Upscayl if you want it.
Will transparent stickers and emotes keep their transparency?
Yes. Fully transparent pixels are handled around the model and the alpha channel is upscaled separately, so the result is a PNG with clean transparent edges.
Can I upscale a whole sprite sheet or many frames at once?
One image at a time here, up to about 6 megapixels. For folders of frames, a desktop tool with batch processing (Upscayl, Topaz Gigapixel) is the better fit.
Curious what "AI upscaling" actually does? Read the plain-English guide, or go back to the upscaler.