Multiple product images, drag&drop and auto image deletion

Hi,
I've been reading the posts about adding multiple product images, but haven't found the right solution yet.
Here's where i'm up to, which is not much I guess:
1. Installed this plugin: http://wordpress.org/extend/plugins/drag-drop-featured-image/
2. Installed this plugin: http://wordpress.org/extend/plugins/multiple-featured-images/

Now the thing is I'm still learning WP and I need some guidance. So far I can add 4 featured images on Posts, but not MP products.
My idea is to make use of the two plugins and tweak them to show multiple product images fields in the admin frontend (the one from Tailored Themes) so the user can add up to four product images by just 'drag & drop'. [One problem I've encountered is that the user can upload the images but there will be no way the user will be able to delete them once they delete the product, using unnecessary space in my server which is why I asked a separate question, but if you have the solution to that please post it here], I think I've sorted out how to display those images on the product page once published, so i'm ok with that last part.

I'm a little confused now and do not want to make changes in files that will mess up the code for future updates. Please, if you need something similar, I'm keen to learn and to work with someone who has some experience to develop a plugin or find a solution to this. Any suggestion on where to start or what route to follow, please let me know.
Thanks in advance!!!!

Regards,
Eric