Improved links panel (with Relink All)
Improved links panel. List all instances of a linked image under one 'primary' link, append the filename with " (xx instances) ". Use a chevron that points right to indicate that there are multiple instances under the "primary" one shown in the list. Clicking the chevron makes the chevron point down, and displays the list of all instances.
Clicking to select the "main" instance and clicking the re-link button should allow the user to replace all instances of the same image. Allow the user to expand the list downward as described above and select a single, or multiple instances to re-link. In this case, provide a pop-up dialog asking whether to relink all selected instances or re-link one at a time, incase the user wants to link different images.
If user relinks with different images, move those new links into their own instance grouping with a "primary" heading of its own.
Image mockup provided for clarity.
Very similar to my own suggestion linked here:
The Illustrator links panel should have a "relink all instances" option just like InDesign, to relink an image JUST ONCE for multiple instances of the same link in one document.