existing image attachments doesn't show up

[Omri Amos]

I noticed that in both posts and users signatures, existing images that are attached to the post doesn't show up (there is an empty space) - and only shows up once you click on that empty space to open the image in the popup modal.

This happens on the default theme with no modifications as well.

Newly attached images works just fine. also, if i simply edit a post and re-add the attached photo to the post itself, it works just fine.

Any idea? maybe some background conversions tasks didn't run?

[SeNioR-]