but if a website dont want there images spread, they must watermark, thats the best and good solution.
No..the best and good and ethical and honest solution is..
If website A didn't make the images..it should not take them from another website B..whether the website B watermarked them or not..They do not belong to website A..
The problem comes when website A thinks, " I'm too lazy to make my own images, but these look nice, I'll just take them, no-one will know that I just took them, and if one day someone complains that I took their images, I will say , but they had no watermark"..
Does the owner of website A have their name all over the outside of their house and their car and everything they own ? ..NO ? ..So the owner of website B could just come along and take them, and the owner of website A would be fine with that ? ..
I don't think so ..
What is worse is when the owner of website A thinks that the images they took from website B ( without permission, and in many jurisdictions, against the law )..now somehow belong to them at website A, and complains when website C comes along and takes them from website A..
And then along comes website D.. and does the same ..etc etc ..
Eventually search engine G shows up..
And shows the images as belonging to websites X, Y and Z..
Moral of the story ?
Don't use images which are not yours, don't scrape images, don't support scrapers,( looking at pinterest , it's clones, and ehow etc ) and, if you want your original images to be in image SERPs, don't let anyone hot-link them, protect them from all the varieties of scrapers, "manual" and "auto" and "crowd sourced", and watermark your images..
Why watermark them..
Because there are many dishonest people on the web..( who will try to "spread" images, especially into their own websites ) and search engines don't always attribute images correctly to their actual creators and true owners, even when they can, and do for the "big dogs", Getty , Imagebank et al..