I've just discovered this, so apologies if you know already. I think it's awesome.

You can drag n drop images off your desktop/hard-drive into the text area of Google Images & it will instantly find similar images.

I tried it with a catalogue pic from OTD of an Autavia.. it found loads of pics of other Autavias!! Great tool for researching watch models etc, or for any other research.

Go and try it!!