Comment 8 for bug 225953

Which theme?
- The Firefox theme is Firefox (default).
- The Icon theme (as I specified before) is Tango, and it does have a scalable version of that icon.
- The GTK theme is the one specified by the gtkrc file I attached before.

I have found that switching the GTK theme (and restarting firefox) to one that requests larger icons stops this from happening (without changing the icon theme). Furthermore, the size of the icon in Firefox is actually what is wrong, other applications use a smaller icon, as requested in the gtkrc file. The Firefox version actually seems to be that small icon scaled up, so if the icon was the right size, it wouldn't be pixelated.

Also I have found the menu icon for "page info" in the tools menu was pixelated, and the menu icons are abnormally small on the GTK theme too, so it is probably ignoring this line of my gtkrc:
gtk-icon-sizes = "panel=16,16 : gtk-menu=8,8 : gtk-button=10,10 : gtk-small-toolbar=10,10 : gtk-large-toolbar=16,16 : gtk-dialog=24,24 : gtk-dnd=24,24"
Other applications follow that line well, so I still think this is a bug in Firefox and not the theme.

I hope this helps.