Centarsia is now postcard-ware! This means you can get an unlimited queue size for the price of a postcard + postage. Centarsia's various user levels are based on queue sizes; user levels refer to how many pictures you want to use to make your mosiac. The user levels have nothing to do with how many mosiacs you can make, only how many images can be used in each mosiac. Up to 400: Free. Just download the program. Unlimited: Almost free. All we ask is a post card (real, not electronic). Interesting ones may be featured on this site. Just send the card to the postal address listed in "Contact" and be sure to include your email address. When we get it, we'll email you a serial number.