If I add a png image with either white or transparent background on a section which is white the image is published with a slightly grey background barely noticable - but it was noticed by one of our customers.
Example here: http://event.altfordamerne.dk/stot-br…
If you look at the 5 bubles upper right or at the bag mid page at right, both pictures have a slightly grey background.
Please try it yourself to see if you can recreate the bug.
Is it a bug? I think I have done everything right.