I have some doubts about "if rot90: img = img.transpose(1, 0, 2)".

[Tangjian2344]

Dear Author I think the effect of this code is to fold the image diagonally instead of rotating it 90 degrees。

[Lifedecoder]

Yeah, you're right, it's a flip over diagonal, but I think it can be seen as a kind of 90 degrees rotation.