On my N9, FlickrIUp tries to show thumbnails to all -- I think all -- of my pics. Not sure, since I lost count around 700 thumbnails. But -- and this is, as they say, the crucial "but" -- not all the thumbnails appear and are instead replaced by the text: "Unable to retrieve". Sometimes the message goes away quickly, replaced with the thumbnail. Sometimes it doesn't. I don't think it's the same pics every time. Doesn't necessarily mean I can't upload the pic with the missing thumbnail, though Naturally, if you can't see the thumb, you're sort of using the force to pick your pics . . . I've never attempted to actually upload more than a dozen or two at a time.

If I had to point the finger at anything, I'd blame Tracker, but who knows.