@Guest_Gina
You can do this all except for the last one (alerting customer for previously purchased products). Good news their are several developers that could do this and I doubt it would cost very much at all, for sure it is less then 1 hr’s work. As far as downloading different file formats you can do this but it would probably be easier on you to just include all the popular formats in the initial download (bmp, jpg, gif ect…)
-Sno
Yes, all available but last in standard cart. You could also use option combinations to associate a different product code to a format and/or have your options identify the format but then you'd have to manually assign the desired file format for download (this is what I do for various versions of the cart when selling addons). If you wanted to automatically associate an option to a particular download file it will probably require custom programming.
Regarding the last, yes it would be about an hour to do this in your my_changes addon whereby when an item is added to the cart, the user's prior orders are checked to see if they've purchased before. But if they were ordering a different format, you might want to just make it a warning/informational versus actually not adding it to the cart.
Hi tbirnseth,
It seems to be taking awhile for my last post to snorocket to get approved, I am hoping this one goes through quicker.
Yes, I don't want to prevent them from adding to cart, just letting them know, regardless of format. I'd probably want something to pop up for warning, and then a yes or No button to add to cart anyway, or continue shopping and not add to cart.
Thank you.
Hi all,
Well I have signed up for a personal demo, and I can add options to my downloadable product, but I can’t figure out how to do what I want, as stated above.
I have a product page, and have options for size and file format to purchase on a set of designs. But I can’t seem to figure out how to assign a file download link for each size and format. If I associate many files to the order page, then on payment the cutomers seems to be able to download all file formats and all sizes that I offer for sale.
I’m confused. 
I don’t have to have a file format option, but design SIZE is mandatory for the cart. I do not want to break up products by sizes on separate product pages, I want some kind of drop or checkbox in case they want multiple sizes. In order history download, I would rather present the file format in a drop down box instead of listing AAALLLL the formats separately as it kind of makes a mess with multiple products.
Can anyone help me out here?
Thank you!! for all the help so far.