GraphicsMagick is a replacement for ImageMagick. Now x11-misc/slim depends only on media-gfx/imagemagick.
Sorry about the mass reassignment, but this undertaking really shouldn't burden bug-wranglers further.
This is more or less a duplicate of Bug 252241 and I'd personally say the dependency should be dropped altogether. It doesn't involved any linking at all and you can use scrot or whatever else for the functionality.
phasing out the imagemagick dep. wontfix this one, thanks anyway.