Osu-web: Map backgrounds are not cropped for thumbnails consistently (?)

[dorothy3242]

Earlier today, when I updated my mapset, the cropping for the thumbnail changed drastically even though the background hadn't changed at all.
Then when I updated it again, it changed to be cropped around her face again like it originally was.
Left is from earlier today, right is from after I updated it again (at 2:57 UTC -4)

https://osu.ppy.sh/beatmapsets/675086#osu/1428231

It seems like there may be some issue with the thumbnailer if the exact same image gets cropped in different locations between uploads. (?)

[peppy]

It’s currently powered by a trained algorithm. Probably due to a difference in compression or similar.

Eventually we will be giving the mapper control over this.

[Ryuusei-Aika]

In my opinion, using a trained algorithm to crop the background image seems not to be the best choice, since not every time it will crop exactly the portion of the background image that mappers want to see.

Should be good if mappers can adjust which portion of the background image they want to show in the mapset page online.

Maybe can add a little edit button next to the preview background to implement this function?

[peppy]

Eventually we will be giving the mapper control over this.