We just moved to a new server and upgraded Exp Eng to version 2.7. I also installed version 5.4.10a of Channel Images on the server. Now when I go to the channel fields setup all of the previously defined image sizes are gone. Saving/updating the custom field deletes them entirely. Also, clicking on the Add new size button does nothing. Something appears broken somewhere. Also, when I click the test file upload location it gives me an error about Cloud settings. We aren't using a cloud service, the files are on the localhost. Any ideas/suggestions?
Apparently this had to do with moving from Exp Eng 2.5 to version 2.7. In the upgrade documentation they now recommend that you replace entirely the system folder by moving your current system folder to system_old. My guess is that there was some old code in the system directory that was causing this problem.
The solution was to start with a fresh system folder directly from the 2.7 install files. Having already done the upgrade I replaced the files, re-uploaded all of my custom files (config and database), and my third party add-ons. Everything worked correctly after that.