Transparent PNG Page Icon Addition

Currently each time you put an icon for a page a greish square appears at the back of the icon. What I would like is for it to allow a PNG image in which the transparent parts of the background of the icon image are actually transparent and that greish square at the back is removed. Here is an example of what I am saying:

PNG icon 2
PNG icon 3


@Marco as there are a few similar or related bug reports and requests, I created this FR:

Would it be OK for you if merge your topic into this one?