Cannot cancel attaching an image into an article after selecting "browse"
1. Hit "Insert an image" into an article
2. Choose "Browse"
3. UI shows existing images
--> There is no way to go back to other selection method or cancel the dialog by hitting Esc or clicking outside the dialog. You need to choose one to close the dialog and then remove it.
Also the title at that point says "Manage Images" which I think is a bit off.
Does the title "Manage Images" give you an impression that there are multiple options to perform with the images? With respect to the actual issue, you should be able to go back to the previous section by clicking on the X (close) icon available in the dialog box.
In case if you're not seeing this option, please check if it works as expected in the private mode of the browser.