It seems that the resize command always forces a resizing operation, even when the new dimensions are the same as the current ones. For performance reasons, could this be changed or an option added to skip the whole resize process altogether in that case?
AFAIK, it is not the case. There are tests to determine if the size are the same, and if so, the same image is returned (in case of +resize) or unchanged (in case of resize).
See lines 33317 and 33346 of CImg.h.
Ah, interesting. I did just the “dumb” test of calling resize in a loop with always the same size and it seemed to take longer with each iteration, but I will test/verify that again today. Thx!