Allow pasting images from the clipboard
When taking screenshots with Ctrl+Shift+Print, the screenshot image is copied directly to the clipboard, without being saved in the Pictures folder. Then it can be pasted in applications like Inkscape or Telegram directly, with no intermediate step, which is very convenient, especially for quickly sharing a screenshot of something you're collaborating on via Matrix.
In Telegram, pasting the image opens this dialog where I can confirm whether this is the image i want to send and add a comment. Sending the image directly on paste is probably not a good idea due to privacy concerns and lack of feedforward for the action.
What I'm proposing is a similar popup with a preview of the image that's about to be sent, and a send and cancel button in the header bar (not sure if a comment is necessary, or even supported by Matrix).