I noticed that after a new site is generated using the New Blog Templates plugin, the image thumbnails in the media library for the newly-created site are not visible. The image file is there, but the thumbnail looks blank.
I also noticed that this happened recently after using the Domain Mapping plugin. All the images are also not visible.
So my questions are:
1. How can I have this not happen
2. Is there an easy way to "refresh" the media libraries across my entire network?