Steps to reproduce:

Prepare the environment:

• Prepare two eZ Publish 4.7 installations, fully patched. One will be the source server, and the other will be the target server;
• Install eZ Content Staging 4.7.1 on both installations. More details here:

https://doc.ez.no/Extensions/eZ-Publish-extensions/eZ-Content-Staging/eZ-Content-Staging-1.x/Installation

Notes:

• When installing eZ Content Staging 4.7.1 in the source server, make sure to use on contentstagingsource.ini.append.php:

TransportClass=eZRestApiEmbeddedClientStagingTransport471

• Also make sure that on wsproviders.ini.append.php the 'providerUri' setting points to v2, not v1:

...
providerUri=http://target_server.com/api/contentstaging/v2/
...

Reproduce the issue:

1. Create a new content object (from 'Image' content Class);
2. Fill in all the required fields, and make sure to fill in the image attribute with an image;
3. Publish the content object, then sync it to the target instance;
4. Edit the content object, remove the image by clicking on "Delete Image" button;
5. Publish the content object, then sync it to the target instance;
6. On the target instance, open the synced object: the original image is still there.