Go to

oc-content/plugins/instant_messenger/index.php

Remove line 27

osc_enqueue_script('jquery-validate');

You will probably be able to republish images again.

Go to your item post page, click with right button and "View page source", make sure that your script have

<script type="text/javascript" src="https://www.yoursite.com/oc-content/themes/osclasswizards/js/jquery.validate.min.js"></script>

Use "CTRL + F" and search for "jquery.validate.min.js" to find it more fast

Maybe the script OsclassWizards or another plugin already have the jquery.validate.min.js, when activate the IM Plugin it goes up and stop work the PIC image on item post, worked for me, maybe it works for you too.

The IM plugin continues to work correctly as far as I tested it.