Allow to set image size in message

[Batwam]

💡 Idea
As discussed on Matrix, it would be useful if there was a possibility to specify the size an the image attached to a message. Currently, images appear to be blow up to full width which in Firefox can we quite large.

I did try to resize the picture hoping that it would show as a smaller thumbnail but it also gets scaled up to full message width which makes it very pixelated. As a minimum, I would propose (if possible) to only scale down but not up.

I also tried to include the picture using html markdown but this does not work as ntfy doesn't support html_markdowns. I don't believe that markdowns currently allow to adjust the picture size. Either way, I can't really use markdowns as they are shown as plain text on iOS (separate issue).

top picture resolution 160x66
bottom picture resolution 1080x475
actual message window width ~700px

💻 Target components
Where should this feature/enhancement be added?
Firefox/Android app as this is where images can currently be shown