Using JCE Pro 2.8.6; the editor's "Images and links" tabbed page

The Images & Links tab is part of the Joomla Article Manager (com_content), not a part of the JCE Editor.

When an "Image Float" value is set, it is applied to a div container of the image, as a bootstrap css style, eg: <div class="pull-left"> Depending on your template, this may have been changed using a template override.

Also, the Intro Image is not aligned relative to the article text, but rather is positioned above it.

As I said in my previous post:

The Images & Links tab is part of the Joomla Article Manager (com_content), not a part of the JCE Editor.

Therefore any classes that are applied, are done so as part of the Joomla Article Manager, or in some cases by a template override.