Itīs also noticable in not (or just in one direction) scaled up images which are quite small like the ones you use when building a GUI and thatīs actually the situation when I noticed it.
When I want to display a window border bar using f.i. a streched 2x16 bitmap I dont care about a possible pixel shift along the stretch. But as soon as I want to use the same bitmap for the opposite border bar by using scale_x=-1; I get the pixel offset.
And since itīs the nature of this kind of bitmaps to contain important color information in just a handfull of pixels, specially in the border pixels, the visual effect can be a completely other one than the one of the opposite border.
Creating multible versions of each bitmaps seems to be the only solution...
...and that makes me sad