Image handling/sizing

I'm a little confused as to how Plone handles images sizes. For example, in Site Setup > Image Handling I have set the "Large" image size to be 700 px:

However, if I create a page and go to insert an image, I see the "Large" option is 768 px, not 700 px:

Shouldn't the Large setting be 700 px per the Site Settings?

That's a hardcoded in the JS File of the TinyMCE-Pattern. But i don't know really how to change this. A Plone JS Hero is needed! Or a good tutorial how to customize the pattern. In principle its a ajax call to a BrowserView that returned the registry values of allowed_image_scales.

It's not hard coded in the pattern--it's part of the pattern options with a default value. Previously, no pattern options were being passed into it.

There was a PR a while ago to fix this that never got merged:

Maybe a workaround could be to just add a new scale ( Mylarge 700:700) ?