Leosghost - 11:36 pm on Nov 22, 2011 (gmt 0)

If you clip off just one pixel ( in a straight line ) from a side of a photo..the metadata is gone..in fact almost any alteration removes metadata..including "resaving" or rotating etc..

If the copying website just "squashes" the original to fit their site via "src" height and width ( you'd be amazed how many sites just do this )..then the meta data is preserved..

Visible watermarking is better ..done diagonally through the centre of the photo..much harder to get rid of ..even with "intelligent fill" ..

Bear in mind if the image "copy" that you are looking for ( ie; you have the original but you are looking for copies ) via tineye is on a page which has "anti-hotlinking" applied tineye will not find it as a match..

AFAIK tineye also obeys robots.txt..

You could always use steganography to "hide" another file in your images ..if the images are altered, some of the second file will be left in the hex code as "proof"..there are other ways..

HTH :)