[16.0][ADD] web_widget_many2many_binary_preview
This module allows developers to enable a preview on fields displayed
with widget many2many_binary.
Easiest way to test this is to edit the view of mail templates and add the attribute show_preview="True" which I just did on runboat
I've tested and noticed that even though you limit width and height to very low numbers (I tried 50x50), and I make the container width very high (by embedding the field in a float: left with eachother nicely. The block with the image and its nearby caption just stretches, and the next one always comes below:
that's what the binary attachment widget does, not sure if we should change this here. Would adding display: flex to the .o_attachments div solve the issue for your use case?