Hello!
We sometimes even deliberately remove previously existing preview support, e.g. last time it was about SVG:
- Desktop ignores viewtype and displays SVG as an image even though it should have a File viewtype from the core · Issue #6049 · deltachat/deltachat-desktop · GitHub
- Support rendering of SVG on mobile.
JPG and JPEG are already displayed as previews, as long as they’re sent as images and not deliberately as files.
IDK if there are plans to display them always as images.
Same with video and IIRC audio, common formats at least.
I can’t see how, besides WebXDC dynamic preview & click listeners (inline apps). If you have to click something then it’s not really a preview.