I would be vary carefull about the use of so called free images from some of these web sites. some of them come by them in less then honerable means.
If you happen to get one that was gained in like maner you could be lible just as well as the site that you got it from.
There is a $5,000.00 fine for copyright infrengement and you are also lible to the copyright holder for punnive damages.
Thought I would inject a wake up call in to the discustion.
Have a good day!
Member of PPA, IFPO