I am having the same problem.
Images in Crystal Deports 9.1.5000 (bundled DOTNET version) do not show up in ASP.NET application. I did EVERYTHING suggested, and now I got to see the CR navigation buttons now, however the images that are part of the report itself do not show up.
I already tried all of the below:
gacutil.exe -i abc.dll (did not work because it wasn't strongly typed)
created a Virtual Directory to CrystalReportsWebViewer2 (that solved showing up of navigation buttons) and created "Application" setting for it
copied abc.dll to the same folder as Crystalimagehandler.aspx (did not work)
gave RWX permissions to the ASPNET user to all the folders in question on this server
I am running out of options, is there anything else that I can troubleshoot?