connecting fronts and backs -- a working gallery

[henry]

Folks:

I'm doing a project that involves collecting old photos, just started using Coppermine. 

The good news is contributors are emailing new images photos, front (emulsion) sides and reverse sides,  almost quite often.  The bad news is I haven't been able to impose any system besides serializing every photo as it comes in.  So, image #80 may be front side and image #130 might be the reverse side of a particular photo.  Any suggestions about mechanisms to link these together as I discover which front goes with which reverse?   

I suppose that I could create a new composite on my workstation, front-and-back side by side, and upload that as an entirely new image.  I'm reluctant to do that because of the completely different resolutions needed to capture photographic detail (sometimes 1200dpi!) and the typically handwritten notations on the reverse side, for which 300 dpi is usually plenty.

Suggestions?

TIA

Henry