It's funny how 'ufo' became synonymous to 'alien spacecraft' in some circles. All the photos alien-believers show are either unidentified objects that might be seagulls, things like a piece of dust on the camera. or photo-shopped.

A picture in which you could actually see a certain craft, clear enough to see some details, might be a bit convincing. If it was taken by NASA, that is, because it isn't as if there aren't thousand of photoshopped 'alien spacecraft' photographs out there.

Really, the question is why nothing but blurry photos are convincing evidence of alien civilizations that travel to our planet, to some. Or the question why not a single half-decent photo has been taken. I would say that last thing was a mystery. But it would only be a mystery if aliens actually came visit us every now and then. Under the current circumstances, there is nothing mysterious about a truckload of vague photos and video images, and not a single clear shot. Since every clear shot turns out to be a seagull, and every blurry shot goes into the 'alien', 'bigfoot' or 'loch ness' basket.