The Text plugin is handling the file type, since it's all text data. (Nothing garbled, that's just the file contents. For some reason the images are stored in a text format.)
I've made a note to see if we can make it detect these files and ignore them, so that they fall through to displaying via a shell thumbnail. In the meantime, the only way (without writing some C++ code) to get them to display as images in the viewer pane would be to disable the Text plugin.
Thank your. I'll try it.
