Digital (Photos) downloads

Hi,
I’m looking for a plugin to sell digital photos.
But I want the buyer to able to pick the size of of the image.
So they see a preview from one of the many galleries, they like it, and then get to pick the size of the image.
ie Low res 5$
Med res 7$
High res 15$
Continue shopping or proceed to the checkout and pay.
Get the image emailed or ideally automatically sent to them when the money has cleared?
Any ideas out there please?