Welcome to the new iTunes 11 world! When Apple updated the iTunes Application, unfortunately one of the things that seems to have gone away is Provider-specific art work in the Tag and Collections pages. Everybody now shares a nice shade of white (Tag pages) or brown (Collection Pages).
One of the more troubling changes with the iTunes 11 Application is the removal of the external URL functionality in the iTunes U space. I'm hopeful that in the future this feature (along with the Provider-specific grapics) will return.
All the best....
SRVideo Media Design
Apple iTunes U Administrator
Tennessee's Electronic Learning Center
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