Caution: The upgrade is available in the USA only. It's strongly recommended to go for a rigid envelope, as large photos can get easily damaged in USPS transfer if not protected. 
 
This is the upgrade of the order of photos from size 4x6" to 8x12" (4x the size). 
 
Instructions:
Order photos you want from Photos Collection (prices are for 4x6" format)
Order this upgrade in number equivalent to the number of large prints from your order
e.g. you ordered 5 pictures of different persons and want all of them in 8x12", order this upgrade 5x
if you want only part of your ordered photos come large, please clearly explain for which the upgrade should be applied