It's quite obviously stolen. I'm surprised they didn't throw the sha sums of the images into the article for good measure.
$20k in damages is an exaggeration. It's not like stampready would have received an extra $20k in revenue if Email On Acid didn't exist. Sounds like Lawyer math to me.
On the other hand, if I'm researching companies, and see a small one trying to sell me something a bigger one is giving for free i just consider them scamers and move on.
How do you calculate the loss of sales for cases like this?
Edit: ...and this argument is totally invalid for what zeidrich said.
$20k in damages is an exaggeration. It's not like stampready would have received an extra $20k in revenue if Email On Acid didn't exist. Sounds like Lawyer math to me.