Why ordinary resizing blurs, and what an AI upscaler does instead.
2× or 4×
2× is enough for most web and social uses. 4× is for print, large screens or cropping into part of a picture.
Start from the best version you have. The detail an upscaler adds is a well-informed guess, not the original detail, so a sharp source gives the best result.
Upscale or enhance?
Upscaling makes a picture bigger. If the problem is blur, noise or compression artifacts rather than size, Enhance details is the better tool; for a small, rough picture, use both.
Upscaling many pictures
Upscale works on up to 8 pictures in one request, and on photos you upload as well as results made in the studio.