Ugh VB sure doesn't make it easy on you. In 4.1.7 all custom avatars are duplicated and re-sized in a thumbs directory, and if you are running GD, you will lose all transparency with the re-sized thumbnails. Now I either have to re-size every members avatar to the same size that thumbnails are to retain transparency, and this mod's functionality
or
switch to Imagemagick, retain transparency and toss this mod aside.