The attached images to issues are not shown in Chromium (88.0.4324.150 ), but they are visible in Firefox (86.0). This is a screenshot from Chromium:
And from firefox:
The images are served as Content-Type: application/octet-stream if that matters.
Content-Type: application/octet-stream
This seems to be fine in Chromium 88 and Chrome 89 (the current stable version).
Chromium 88 from Fedora:
Google Chrome 89: