Question 1

How is AI upscaling different from simply stretching an image?

Accepted Answer

Plain stretching only smooths the pixels and the picture turns blurry. The neural network draws in plausible detail, removes JPEG blocking and sharpens edges. It is a reconstruction, though: if the source had no information, the result is the model's best guess.

Question 2

How far can I enlarge, and what are the limits?

Accepted Answer

×2 and ×4 are available. The source can be up to 1.5 megapixels (about 1200×1200), and on iPhone and iPad at ×4 up to 1 megapixel. Speed depends on your CPU: an image of a few tens of thousands of pixels takes seconds, around a megapixel takes a few minutes.

Question 3

Are my files uploaded to a server?

Accepted Answer

No. The model and all computation run in your browser and the image is never sent. Only the model itself (about 5 MB) and the ONNX Runtime engine are fetched once, then the browser serves them from its cache.

Question 4

Can it improve faces, old photos or logos?

Accepted Answer

The model is general-purpose and doesn't restore faces separately, so faces and small text can look unnatural. For logos and icons vectorising works better: SVG scales without quality loss.

AI Image Upscaler Online: Enlarge Photos ×2 and ×4

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