I have used Firefox and XnView as viewers. Apng files made with paint.net that are larger than ~200x150 have open errors with both programs. Apng files that are 150x112 or smaller open with out errors. I have found some larger sample apng files that open without errors in both programs.
I am having problems getting the quality I want. With agif I run into the color limits. With apng I run into a problem where I have to reduce the size to about 150x112. If it is any larger it will not load into a viewer. Is there a size limit for a apng?