The changes to `dlls/gdiplus/graphics.c` do seem obviously correct to me, as it makes array access more contiguous.
Also note, the commit message could be read as saying that the 'fix size' changes are part of the performance improvement. I've already suggested that you remove the `image.c` changes, but if you do keep them I would at least recommend putting those in a separate commit, since as you said they were separate from the actual performance improvements.