Ok, i know i have gotten images transparent before with autocad, maybe it was 2012, but i finally conviced my boss to get me a copy of 2013 with raster design (we used 2007) and it will let me fade images but not let me go transparent. Please tell me how to fix this or get it to work, because this was one of the main features and reasons i gave him for upgrading.
When using fade effect for images, background transparency color is ignored. You can do the same if you set both background transparency color as usual (select image and set background color in properties palate) and transparency for layer with raster images. Don't forget to check "plot transparency" in plot dialog.