The feature is now almost ready. In the same task, I've simplified room configuration.

The last thing to do is to make this work during initial room creation.

I checked the feature and it generally works but: can it retain picture compression/format? I have simple png file of 15KB, but BeagleIM (or macOS photo UI) converts it to image/jpeg, which then after base64 puff up to 69KB of CData.

@wojtek No, it cannot. macOS photo UI gives me raw image which I need to scale and encode. I needed to select one compression format and decided to go with image/jpeg as usually, it generates a smaller image. We can argue what is better but if users will use images (photos) using jpeg will make it better. I decided to use this photo UI as it allows user to select part of the image, etc.

OK. This seems like the most sensible solution.