transparent backgrounds

There are some images with a white background which should be transparent I guess. Often this does not make any diffence at RHP, but at timeforchess for example.
/img/mv/tbwarn.gif
/images/controls/bk.gif
/images/controls/fw.gif (and the other two)
not really important, but iff you want to relax: it's even more beautyfull..
th