It's easy.

When you start comic life go to File/Page format. You have loads of options there. If you rendered an image at 1024x768 like I said before, then tick custom size in comic life and put in 1024x768.

Then drag and drop your image in and I guarantee you won't have degredation.

If you want to use A4 size in comic life, then your rendered image needs to be that size or pretty close to it also.

Injustice will be avenged.
Cofiwch Dryweryn.