Dropdown display doesn’t match available sizes

I am adapting a child theme of Libre2 using a local server.

While this plugin is recognizing all the different image sizes that my theme creates, it does not label them appropriately in the drop-down menu that the plugin creates. Meaning, it’s pointing to the right image URL that I want, but the drop down menu text is something different. How can I edit the menu labels in my child theme?

Thank you.