Continuing the discussion from Animate an image to centre of the screen and 90% of the screen width:
Indeed, being able to select all~none for the "optimize images" feature would be valuable especially if it was accompanied by a "status list" where all the images in the project were displayed with an "on~off" check box next to the file name.
When You only have a handful of images the current regime is adequate. But when the number starts climbing above 20 or so it becomes progressively harder to track the status of individual images. Also, such a list would make it easier to spot potential issues at a glance.