I think the problem here is that the plugin appears to override custom avatars with the default blue Gravatar icon.
I came here looking into just this problem. I installed Easy Author Image 1.5 and the author photos seem to work fine, but all the comments on the site switched to the default Gravatar icon from the custom one I had set up.
I also see the problem on the Discussion Settings page in WP admin, where all the icons listed changed from the various 32×32 images to a single 64×64 Gravatar logo repeated over and over for each option.
The problem seems to be in easy-author-image.php
line 218. The Gravatar URL does not include a fallback path for the custom avatar set up for the site. I’m not familiar with this core functionality off the top of my head but I suspect there’s a WP function that should be called here instead of using a hard-coded gravatar.com URL. (This will also all for loading gravatars via SSL, which is also currently unsupported.)