Check out the print service through the artifact uprising mobile app.  They offer a square print set that lets you print straight from your instagram account or camera roll.  The 5" x 5" prints have a white border and a textured matte finish which I paired with 5.5" envelopes from paper presentation that fit the cards perfectly.  I plan on using these cards for birthday and thanks you cards. I am looking forward to creating a second set, customizing them with photos of friends and family.  natural kraft square envelope 5.5" x 5.5" - 25 pk