Upscale an image in the browser (and what “AI” really does)

“AI upscale” is a marketing sentence. The useful sentence is: a super-resolution model guesses a denser grid of pixels from the ones you already have. Real-ESRGAN is the research line most free tools, including desktop Upscayl, sit on. StackImage runs a similar class of model in the tab after a one-time weight download. Your photo is not posted to an upscale API.

What you should expect

• A 400-pixel logo can become a cleaner 800 or 1600. Edges look less jaggy.
• A noisy phone crop will look sharper and a bit plastic. That is invented texture.
• Faces, type, and fine fabric are the first things to inspect. The model does not know your brand.
• 4× is slower and hungrier than 2×. On CPU it can take a while. That is the device working, not a queue.

1. Open Upscale Image. The first visit downloads model files from our storage. Those requests do not include your photo.
2. Drop a phone photo and pick 2× or 4×.
3. Wait for the pass, then download. Compress if you need to email the large result.

When to use something else

Use Upscayl if you want a local desktop app and bigger tiles. Use a paid cloud upscaler if the job is a client deliverable and you accept the upload. Use a real photo or a vector if the source is a 64-pixel favicon. No model will turn that into a billboard without making it up.

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