Can't delete thumbnail for a document

Hi,  Just installed latest update: 1.23.3 after upgrading my site to Joomla 4 and I can't seem to remove a generated thumbnail for a document.

I made sure the config settings are set to not show thumbnail under Themes tab. I've tried to delete the file and upload the file again and same result.  Not sure what I am doing wrong. 

Couldn't find an answer in forum. Thanks.

Hi,
You can disable the plugin: Auto Generate thumbnail to prevent Edocman to create thumbnail pictures for documents automatically
Thanks
Dam

Wow totally missed that plugin. Thanks for the quick reply

You're welcome