Re: svn icons in the toolbar

[Richard Stallman]

    Aesthetically, the XPM icons may be serviceable for a fallback but they 
    aren't "good enough" when the other programs on your desktop are using 
    PNG or SVG icons.

Why do you think XPM icons are not good enough?
What is better about the PNG or SVG icons?

Joakim wrote:

    I can understand that SVG:s are superior when scaling of course.

Does Emacs do scaling of toolbar icons?
If so, when, and why is it important?

Leo wrote:

    > Does the png library handle alpha channels and
    > anti-aliasing to the background conveniently

    You said it.

I don't understand this -- what are "alpha channels"?  Maybe I
understand "anti-aliasing to the background", but the background for
the toolbar is trivial, right?

Can someone explain what different this makes
_for the toolbar_, and when and why?