If I now click on "Insert", the URL is not entered. The image must therefore be selected again. If I have edited an existing image and click on "Update", the new width and height specifications are also not adopted. If I have saved the image under a new name, this is also not adopted by "Update".

This led to confusion for one of my customers, as after clicking on "Update" he naturally thought that the image selected in the file selection pop-up had been adopted.

This makes sense and I am looking into it. The change may include the existing image properties (width, height) being update after editing, or the edited image being selected for insert if no other image was already selected.

The Image Manager is a sort of hybrid layout, in that it includes editing (delete, rename, edit) of all available images, while including options to select and insert a single image. For this reason, to select an image for inserting, you need to click on the name of the image. Checking a checkbox of an image or images does not "select" the image for inserting, but does allow the images to then be edited (delete, rename etc.) without affecting what has already been selected for inserting.