This can be reproduced in the default alloy site installed from the VS extensions, which currently uses epi 10.0.1. But I have also reproduced it in a site running Epi 10.3.2 and Epi.UI 10.4.0.
1. install a clean alloy demo site from the VS templates
2. Edit any image, ex "For all sites"/Alloy Meet/AlloyMeet.png
3. Change the copyright field and publish the image (doesnt matter what, jsut trigger a change so you can publish it)
4. Open the versions gadget and select the old version of the image.
5. Open the publish options menu and select "Republish"
The published version of the image is now broken (The BlobData property is null if you would look at it programmatically), the only way i found to "repair" it is to select an old version where the image is not broken, select "new draft from here" in the publish options menu, and then publish that version.
Note: I have also attached and looked at the contentsaving and contentsaved events in code, and when contentsaving occur, the blobdata reference is there, but when the contentsaved event is hit, the blobdata property is null, which seem to be the only difference.
Seem to be the same as this bug: