I see no harm in showing the resizing controls in the preview unconditionally for three reasons:
The first is that we only “hide” them with opacity
which means they still occupy some space even when they’re invisible. The wrapper is absolutely positioned, but we add some padding to .image-wrapper
The second is that the feature would then work on mobile as well, which it currently doesn’t for me even though it’s supposed to work
The third is that it would increase the discoverability of the feature.
Short of that, what we can do is make it so that the controls for all images are visible when you hover the preview panel, not individual images. As well as fix the issue on mobile (which might only be limited to my devices)
If we make the controls unconditionally visible, we can also spend a bit of time on making them look nicer.