Help With AS2.0 flash + php registration page

Hi guys, i need some help with this registration page. I know how to submit plain text variables but what if its a picture? I have some JPEG pictures that a user should choose from with the registration. Each picture i want to assign an ID so as PHP can process it. Is there anyway i could do this? Like assign an ID for the image or something?

The picture is browsed with a scrolling system like left right to choose. As they have chosen the picture they want, how do i send the information to PHP to let them know this image is chosen since its not a text and cannot be sent as a variable?

Help is really appreciated, Thanks.