They are supposed to classify it as a package, but some Post Offices don't. All depends on the clerk. Difference is not that much domestically, but internationally it does raise the price.

What I've done on the US side when needing a photo returned from Europe is to send only 5x7s, a 6x9 envelope and a thin piece of cardboard with $3 USD so it can be returned to me. Maybe doing something similar may work for you.

Thanks for that, I'll give it a try. I've had a couple of pics bent by Royal Mail despite writing 'Please do not bend' on the envelope!

I always use just a normal C5 paper envelope (99% of the time I send my own 6x4 picture), never had anything come back bent!

Hi,
I'm based in the UK and want to try sending return envelopes to the US but I am a bit confused by the USPS website. Am I correct in thinking that a board backed envelope (i.e. does not bend easily, as their website states), would have to be classed as a package? If so, this doubles the amount of postage required!

Could I get away with just a standard envelope and would that be enough to protect my pictures? I'm curious to know what other collectors from the UK have tried.

Thanks!