Image USB, or "Burn to USB" was introduced in APM v10, and allows users to select images at the kiosk to be copied onto a USB drive from Lab 50 or Print 50.
The USB, DVD and CD are all what we call Image Archives. The user can only pick one of these archive types per order... so she could not order both a DVD and a USB in the same order.
There are two ways the user can buy an Image USB.
Method 1: I know what i want!
I want to choose my images, and have you put them on a USB!
Here, the user selects the archive product group from the main menu, then picks USB Drive (this is where your short name comes in), then chooses the images to be included on the drive.
The prices here are whatever you set in the fulfillment you marked as default for the archive product (from Step 2 above). If you have quantity prices set, the Price box will keep up with the calculation as the user changes the quantity.
Method 2: I was upsold!
I put in my prints/creative order, but what's this I see being offered, an Image USB!?! Yes please!
Here, the user opted for Prints (or could have done a creative product too), and when that is done, was presented with the option to add an Image USB. If you have the Image USB set up for multiple enabled fulfillments, the pricing for whichever fulfillment the user picked will be used. With this option, the user can choose to include all the photos from his or her session, or can elect to use only the ones he or she has ordered.
The Image USB is made through Lab 50 or Print 50. There is no option to create the USB at the kiosk, like you can do with discs.