I have used them and have had friends that used them. It's a really cute idea. You just upload the desired photo to their website and follow the instructions to place your order for postage. They mail you (snail mail) the completed stamps; you don't print them out yourself. It's real US postage in the amt you specified (and paid for) but with your own uploaded image. There is a barcode-type of image on the stamps that allows the USPS to know that the stamps are valid postage.
Allow plenty of time for order processing and mailing, don't wait till the last minute or it just won't happen. I can't remember if it was a 1-2 week turnaround...? Really cute for invitations or other special mailings. You prob. saw from the site that it ain't cheap, I think it's like 50c or 75c or so per stamp PLUS the cost of the postage itself, so that each stamp runs you round about a dollar.
I've used them a few times . . . never had a problem. The website is really easy and walks you through adding your picture. I did my save-the-date stamps and wedding invitation stamps through their site. It took about 5 days both times to get my order.
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