Yep you guys got it.  There is community of people who mainly used Paintshop Pro which has a feature called tubes. 10 or 5 years ago Poser Tubes were really popular.  In short you can almost think of them like clipart that was created by using renders from Poser. The users would take the images and turn them into Paintshop Pro tubes.  If you have a website you can probably make a few dollars from selling Poser renders for use as Paintshop Pro tubes.