Hi,
1. Deleting images from NameMapping will not affect anything.
2. Probably some of your application elements have dynamically changed properties. Better if you will provide more details on your application, problem objects and its properties and values and so on.
As for storing the images and turning it off, if you have not found it already, on the NameMapping page where you edit your mapping, across the top of the panel is a "gear" button (it's a gear in TC 12.40... in TC12.31 I think it's a drop down control). Click there and turn off the option for storing images.
