Frame them right away then you don't have the problem.

good question..

i keep mine laying down flat.. would love to know the answer too even though i have a feeling that theres no correct answer to this .. most likely a personal pref.

I know there is a big discussion of how to store photos in Collecting Help Forum but I didn't see this question and that forum is dead, so:
This may seem somewhat silly but when you think about it - it makes sense.
I know all about archival and acid free and binders but: What is the correct way to position the binders. I have my binders standing up to take pressure off the photos squeezing against the protective sheets but then I noticed that if I take one out of the sleeve is starts to curve because it is stored somewhat loosely by being stood up - exactly the problem I wouldn't have if there was pressure keeping them flat. So, what to do? Thanks.