Add ability to open image in pop out window

**Is your suggestion related to a problem? Please describe.**
I use Element Desktop in a fairly small window, so it's impossible to get a larger view of an image without either maximizing the window or saving the image to disk, neither of which are very convenient.

**Describe the solution you'd like**
Being able to open the image in a larger separate window would be very nice solution to this. I'm not sure how possible this is from a technical perspective, with how web apps work, but it's the best idea I can think of. Perhaps it could just open a generated page with the image shoved in directly as base64?

**Describe alternatives you've considered**
Only other way I can think to accomplish the convenience I'm after is low level changes in Matrix to allow images to be loaded via a special HTTPS link in a web browser.

**Additional context**
My window is about 690x720, so the view I get by clicking on the image is actually smaller than the preview thumbnail, due to the info text and download button on the right.