Cache all image reps; cache by path extension as well, and avoid using Omni's method.  
Cache all image reps; cache by path extension as well, and avoid using Omni's method.  

git-svn-id: cb3fc60f0f557b927b8032d8a94e869b6f9f230b@1156 0fceea05-a30d-0410-8a8b-80ef821fb0a1

camillobruni/skim,camillobruni/skim,camillobruni/skim,jasongrout/skim,camillobruni/skim,jasongrout/skim