gbk666 - 3:16 pm on Feb 7, 2013 (gmt 0)
an additional php file should not be the problem thats how i did it as well
Trust me, watermarks alone are not bringing a lot though. Redirecting people who want to see a fullsized image directly to your normal page is more useful. Through that i gained around 40-60% of my normal traffic back.
Look via the image search and you see darkend thumbs + after clicking to see the original size you land on the normal website