Use absolute path to skin source as a workaround for Bug 3126 - skingenerator.flm gets the value of EXTENSION_ROOT incorrect

-c16,8 qgn_prop_link_embd_large.bmp
-c16,8 qgn_prop_link_embd_medium.bmp
-c16,1 qgn_prop_link_embd_small.bmp