see http://bugzilla.gnome.org/show_bug.cgi?id=362922#c4 for png and svg files from andreasn.
Using icons included in Xarchiver, should solve the licensing issues.
oh... need to use different icons... xarchiver icons are not GPL compliant
Fixed in revision 24702
you still use wrong sizes of the icon: in the menu you should use 16x16 and in the toolbar 24x24 which are created by using the 22x22 with a transparent 1px border. you can easily create the 24x24 by using convert -bordercolor Transparent -border 1x1 tango_size.png gnome_size.png whereas tango_size.png is the 22x22 and gnome_size.png is the 24x24px icon. the 16x16 icons can also be used in the thunar-archive-plugin, which currently also uses icons based on original tango artwork and thus is not gpl compliant. btw, the "add" icon you use atm has a blue arrow, but the thunar plugin icon for "extract to" uses a blue arrow too. the green arrow you use for "extract" is used for "extract here" in the t-a-p.