When sending multiple images, they all appear one after the other. It is frustrating because if you send a lot of images, it disrupts the flow of conversation and in group chats could be annoying for other people.
Telegram solved this problem in a pretty cool way, as this screenshot demonstrates:

This relates to the android client, but could also as well relate to the web and iOS clients.
Thanks for the suggestion. It first has to be decided at the spec level: https://github.com/matrix-org/matrix-doc/issues/2289
@bmarty thanks for pointing me at that issue! Should we leave this one open as the "interface-side" suggestion and the other one for the backend part of it?
Hmm couldn't this be a pure client side thing as well? I mean the simplest approach would be to simply combine multiple consecutively sent images from one person into such a thumbnail gallery thing/view...
AFAIR that's how it was implemented in e.g. Whatsapp (at least initially)
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Thanks for the suggestion. It first has to be decided at the spec level: https://github.com/matrix-org/matrix-doc/issues/2289