We really need some sort of thumbnail or at the very least a default icon for non-image file types (especially PDFs).
(I'm currently looking at this post for help with this - http://omeka.org/forums/topic/icons-for-sound-files - but I haven't gotten it worked out yet. Would really be nice if this was just a part of Omeka's functionality and didn't require tweaking. Am I missing something obvious?)
Have you seen this? It might help:
It does a bit. I've successfully called the function in items/browse.php, and I now see a link directly to the object where there is no thumbnail. Not positive on how to set it up with a default image for, say, all PDFs or MP3s yet, but I'll poke at it. It would really be ideal to have PDF thumbnails, though. Going to continue poking at that too, but our users would be happier if it did this for them in a way that doesn't require changing code.
(...though I did just read the suggestion to upload a small image file first as an extra file attached to the item, and this might be a workaround for my users for the time being.)
Did you figure this out? I'm also looking for a generic thumbnail for pdfs, audio files, websites, etc.