how do I remove the tineye context menu entry

Hello

To complement

Is it your question

TinEye Reverse Image Search https://addons.mozilla.org/firefox/addon/tineye-reverse-image-search

About there are actually many context entries in Firefox

A space for users to give product feedback https://support.mozilla.org/en-US/kb/what-mozilla-connect

Ability to edit context menus, remove unnecessary options https://connect.mozilla.org/t5/ideas/ability-to-edit-context-menus-remove-unnecessary-options/idi-p/8003

Screenshot 1 with the help of Browser Toolbox https://firefox-source-docs.mozilla.org/devtools-user/browser_toolbox/index.html

Screenshot 2 a test with the help of userChrome.css

#tineye_ideeinc_com-menuitem-_tineye-firefox-ext{display:none!important;}

thanks @TyDraniu.

You were correct.  I found it to be an extension.

I never installed it--to the very best of my knowledge.
I submitted a report about it in the extension's reporting system.  

I do use Yandex.com/images. And it is possible this extension has existed for some time. Righit-clicking a web site image THAT SHOWS THIS OPTION has never occurred before.