[TYPO3] offer download of items in basket

[Michael Paffrath]

hi!

i made a little shopping basket where the user can store pictures from
a gallery (based on DAM).
now i want to offer the user to download all pictures - after clicking
on the button download a zip file should be offerd to him/her.

my question to this is how i could do this, if anyone already did this
(i guess so) or if anyone can point me to a solution (or an existing
extension)

so long,
michael