As per the pre-1.7 thread here -    All images get a transparent border. The issue of the previous thread remains - that when you zoom in and out, at certain zoom levels, images within a file get transparent borders of a pixel or two, making it seem as though images are not correctly placed. It was originally thought that this transparent border was a visual issue only, but I have noticed upon exporting images that sometimes the transparency is baked in to the exported file.