What image sizes qualify to be added into the 'Wallpapers' section?

I've been finding the same problem for years. The information on the right of the Add A New Image page says that প্রতিমূর্তি 600x800 অথবা larger should be ok for দেওয়ালপত্র (only those which are smaller are relocated), but I've had many which my computer says are larger go to Photos. Perhaps it's only a specific size, not anything above a minimum.

There's a way to stop having to সম্পাদনা an image to put it in Fanart though: click "upload fanart" when আপনি উঠিয়ে রাখুন it and then change the drop-down box to Wallpaper. It ought to go to দেওয়ালপত্র if it's large enough but Fanart otherwise.