That message will pop up when we try to load the full resolution image, but something goes wrong. This can be caused by a couple of things.
Some images are inherently broken (they shouldn't have been returned by the search engine in the first place); this is uncommon.
Loss of internet connection: the device can no longer connect to the internet at all. If you still have working internet and you can perform more searches, then this is also not the case.
Restricted internet: the app will go to whatever website the image is from; if you are on a restricted network, it may have access to our server and to bing.com (where the thumbnails are stored), but may not be able to access the actual site because it's blocked by the network. On school networks this may sometimes be the case.