Idea: Upon image upload, the alt-text associated with that image is entered. That alt-text would stay with the image, as the default alt-text, when it is used on a page. You should still allow the alt-text content to be edited on a use-by-use (page-by-page) basis, but the default behavior would be that we could enter alt-text for an image once, when we upload it, and then that is the default alt-text for the image when it is used on a page. If you want to change the default alt-text for an image, you should be able to do that in the Files -> images area.
Why: I use several images repeatedly in my modules. Each time I use an image, I need to replace the default alt-text of the file name with a meaningful name. Over and over, I am re-typing the same alt-text for a given image. From an accessibility perspective, is there any reason why we would want to be forced to do this?