An online survey of young adults in Western English-speaking countries examined the sharing of intimate images. Among participants who reported sharing someone else's images, only 19.8% said they had permission. These self-reported data come from a specific age group; they are not an estimate of everyone's behavior. But the principle is clear: agreeing to receive intimate content does not mean agreeing to forward it or show it to others.
You can agree in advance on whether saving images or taking screenshots is okay, how to delete material if asked, and what to do if one of you no longer wants to continue the exchange. You do not have to include your face or identifying details if that feels safer. And nobody has to prove their trust by sending intimate photos. If your boundaries do not match or someone is being pressured, pausing is a complete answer. Intimacy is built not on how much is sent but on respect for another person's vulnerability.