well installing Imagemagick to use with vbulletin and a gallery would be different so if your using the instructions here it would work with your gallery but most not with vbulletin registration image since that requires you also install FREETYPE on the server as well. You sure in the gallery setup you have the gallery set to use the right processor and the path to mogrify is correct as in the gallery admin is the place to set the path not in your
vb options.