When I was using shell integration more often, pre x64, there was an app called Piky-Basket (IIRC).
I twas integrated into the shell so you could add items to a virtual basket in Explorer. Pre-MC it was a grat tool, but I feel this would be a terrific addition to MC.
We can now copy/move files but often if I want to attach multiple pictures or photos to an email I find myself stuck when things lie "out of reach" in other tag or view schemes. Today I saw a pic I wanted to mail and also remembered another that was somewhere else in the library. The process of copying files to disk, navigating there with MC, and then attaching files to an email is a lengthy process compared to what a basket option would offer. I guess an easy way to workaround this would be to build a playlist as you find images you want to email but it would be quick and easy to have some kind of "email basket" (that Piky-Basket app was so handy).
DC