Sharing a picture from another app doesn't allow to provide a caption

### Your use case

#### What would you like to do?

When I'm sharing an image from another application, I'd like to be able to provide a caption, after selecting the room in the list. The only way to provide a caption at the moment is to save the image locally on disk, then open EXA, then find the room, then send the image, then provide the caption.

#### Why would you like to do it?

I love this behavior in other apps, like Signal. And I tend to want to add captions to most images I'm sharing.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

### Are you willing to provide a PR?

No