BL-3717 Don't cleanup unused images
BL-3717 Don't cleanup unused images

until we load a book (ExpensiveInitialization)
BloomBooks/BloomDesktop,gmartin7/myBloomFork,andrew-polk/BloomDesktop,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,JohnThomson/BloomDesktop,JohnThomson/BloomDesktop,gmartin7/myBloomFork,gmartin7/myBloomFork,andrew-polk/BloomDesktop,gmartin7/myBloomFork,JohnThomson/BloomDesktop,BloomBooks/BloomDesktop,StephenMcConnel/BloomDesktop,andrew-polk/BloomDesktop,andrew-polk/BloomDesktop,andrew-polk/BloomDesktop,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,andrew-polk/BloomDesktop,JohnThomson/BloomDesktop,gmartin7/myBloomFork,JohnThomson/BloomDesktop,BloomBooks/BloomDesktop,gmartin7/myBloomFork,StephenMcConnel/BloomDesktop,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,StephenMcConnel/BloomDesktop