I think if the artist makes tattoo design of his own, original and cool ...it should not be reproduced by copying from photos on internet and stuff...
Another thing if artist makes a flash set and sells it...as soon as it hits a market it becomes for grabs to everyone...and can be copied, reproduced, resold...and such. But it should always be associated with the original author...and bring him if not the money at least respect and recognition...
Copying someones work and adding your name on it is the worst you can do...and should be not tolerated...