Looking for a waifu2x alternative
If waifu2x rejects your file size, or you would rather not upload artwork, run the same model in your browser.
If you have been using waifu2x and hit its file size cap, or you have started to think twice about uploading unreleased artwork, the practical alternative is to run the model in your own browser instead of on someone else's server.
What waifu2x does well
It is worth being clear about why waifu2x became the default recommendation. It is free, it has been available for years, and its model is specifically tuned for illustration rather than photographs — which, for a lot of people, is exactly the job. None of that has stopped being true.
The friction shows up at the edges: the processing happens server-side, so every image has to be uploaded, and there is a cap on how large a file you can send.
Where the two differ
| waifu2x | In-browser processing | |
|---|---|---|
| Where processing happens | A server | Your own machine |
| Upload required | Yes | No |
| File size cap | Yes | Up to 12.6MP |
| Scale factors | 1.6x / 2x mainly | x2 / x4 |
| Models | Illustration-focused | Photo and illustration |
| Price | Free | Free |
The row that changes your workflow is the second one. Everything else is a difference in degree; that one is a difference in kind.
Why the upload step matters more than it used to
For a doodle, uploading is a non-event. For a commission you have not published, or for a client's asset covered by an agreement you signed, the upload is the part of the process you would have to justify if anyone asked.
Running locally removes the question rather than answering it. There is no retention policy to read, because there is no copy to retain.
What you give up
You download the model once. About 11.6MB, cached afterwards.
Your hardware does the work. On an Apple Silicon laptop, a 1024-pixel-square image at x4 finishes in about 7.1 seconds with the photo model and about 3.9 seconds with the illustration model. On a slower GPU it takes longer — there is no server to absorb that for you.
You need a browser with WebGPU. Recent Chrome and Edge qualify. waifu2x has no such requirement, because the work is not happening on your machine at all.
Trying it
Open Pixmend, drop the image on the page, pick x2 or x4 and the illustration or photo model, then compare the result with the slider before downloading. There is no account step, and no upload step.
If you want to confirm the claim rather than trust it: open your browser's developer tools, watch the Network tab while you process an image, and note that nothing carrying the image appears.