I've been looking at other member's cards to see what y'all are doing and I find those optional watermarks really annoying. So I went back and took them all off my own images. I'm deliberately not selecting that option for my images. The card image that is displayed to the public is waaaaaay too small for anyone to casually reproduce or "steal" it for marketable purposes when captured with a 96 ppi frame grabber! So what's the point? Frankly I think the sample display is too small to really see what you are getting, especially for photographic images with a superimposed small lightweight type face and if I was shopping for a card I'd be hesitant to buy it based on the low-rez, teeny-weeny display. And adding a repeating watermark, well that adds to the problem. Any one here ever have problems with customers pilfering your artwork?

This is exactly why we made the watermark optional.  
 
There was quite a debate with parties on both sides of the fence:
http://www.greetingcarduniverse.com/forum/yabb2/YaBB.pl?num=1172089671/0
 
As for image size, yes, the thumbnails are fairly small in an effort to get a nice sampling of many cards in an eyefull.  All thumbnail images have an easy and larger rollover image.