Method
"General photos" keeps the grain and fine texture, and suits portraits and landscapes; "strong denoise" cleans noise more aggressively at the cost of smoothing texture too — best for old photos, phone night shots and heavily compressed JPEGs.
The model is a 4× one: picking 2× or 3× scales to 4× first and comes back down, which looks better than scaling directly and takes the same time. The model ships with the site and loads locally (a few seconds the first time). No external servers.