Help with "Insert Module"

The insert module allows for the placement of images and files into the content body area from within the CKeditor. I have installed the module and it works - images are placed wherever I want with text before and after.

My problem is in working out HOW to set things up so the small image on the page opens in a colorbox at its full size. As far as I can tell the images are being uploaded in full size (1024px width)and when the page is saved, they display in the smaller 200px width. Clicking on the displayed image opens a colorbox, but the image displayed in colorbox is only 200px wide.

I've searched far and wide to try and find a tutorial that explains how to set this up and which combinations of settings to alter in order to achieve a display this way. No luck so far so turning to the Community to see if anyone can help.

Colorbox is set up to use the image style "Image Insert Field" (under Insert Module Settings), Styles and Options is set to use Style "Default", Colorbox Options is set to "use custom options", Max width for loaded content is "1024", Max height is "768".

The Default Page has a field "field_insert_image" with max image dimensions set to "1024x768px", its Preview Image Style is "Original Image Size (1024x768)" (I set this up). Still working with the Page, under the "Insert" section, I have enabled the insert button, enabled insert styles "link to file", "Colorbox Image Insert Field", Colorbox Large (800x600)" and "image_insert_field", set the Default Insert Style to "Colorbox Insert Image Field", and Max Image Insert Width is set to "1024" pixels.

The Default Page (under Manage Displays) has the field Insert Image set to "Hidden/Hidden".

I think that's all I can tell you....

Using:   Linux on Debian 10 VPS, php-fpm 7.3, Backdrop (version unknown - downloaded 4 weeks ago)