Checkerboard background for transparent

[JanisV]

In my opinion, it would be better when the background is colorless to put a checkerboard background (I don't know exactly what it's called). Somehow this seems more appropriate to me, and it's used almost everywhere when you want to show that the background is colorless. There are images with such a background in this article https://www.qt.io/blog/vector-graphics-in-qt-6.8

[JanisV]

This dialog is also used for viewing, the chessboard will not be very pleasant, especially in the dark theme. Apparently the viewing and editing mode should be separated