Definitely one of the best upscaling tools I tried so far, although for particular cases, you may want to use different tool. I tried it with various kinds of images and photos, and this is how I see it.

PHOTOS: here is the example - zoomed up part of screenshot of YouTube video; comparing original, upscaled version from Gigapixel AI (my preferred photo upscaler so far) and Img.Upscaler. I recommend to download the image and see that, because pCloud shows only preview in lower resolution: https://u.pcloud.link/publink/show?code=XZe7prXZLc14GYakSGSid3wGgLFGluWTw7bX

Subjective summary: when zoomed in a lot, Gigapixel AI’s result looks more identical to original, but also is not very sharp (consider here, that the Gigapixel AI’s result is 10000 pixels in width, while Img.Upscaler’s one only 5120 due to limit, so I would expect Gigapixel AI’s result to be the sharper one). If you look at the zoomed result of Img.Upscaler, you can see that everything is much more sharper and colors are slightly improved and cleaned out from artefacts, but also some areas seems slightly weird (notice the part where tracks are disappearing in distance, or the plants on the left having some kind of moiré on them). But if you zoom out slightly so the problematic areas are not scaled as much, suddenly Img.Upscaler result as a whole seems to look better. Also I tried to print all 3 pictures to A4, and I definitely prefer the Img.Upscaler’s result. And also I have to note, that Img.Upscaler have fantastic result with photos of objects (I picked the photo above because is is probably best for showing the problems due its complexity, and it actually being one frame of moving video).

IMAGES: here is the example, again, I recommend to see the downloaded version: https://u.pcloud.link/publink/show?code=XZP7prXZlWW0DWykiFyKnvbO4VrUgSDAyW1X

This time, it is just original and the result from Img.Upscaler, because considering the quality of the original, it is almost perfect, and you can see on the lines that they are actually redrawn and not scaled. The only problem I can see is that some lines in the heavily striped stripe are blurred, but this is already in the original image due the low resolution, so I understand that AI is not a prophet. I tried also different images including the coloured ones, and all results are as good as this one, including the combinations of drawn images and photos.

Conclusion: if you need upscaling of photos, want to save time, do not need the results at super huge size (billboards etc.) and prefer the results be more eye-catching and sharp, definitely give Img.Upscaler a try. If you are a professional photographer or graphic designer who looks only for photo upscaling, and then you spend another hours with adjustments in other software anyways, then looks elsewhere because some changes in the upscaled version would be too much for you. And for upscaling of drawn images, I definitely recommend Img.Upscaler no matter who you are. (continues below)