how can I insert a placeholder in Illustrator
how can I insert a placeholder image in Illustrator, the way it can be replaced by an external real image file.
Drag and drop the placeholder image onto your Illustrator artboard.
When you want to update the placeholder you can go to the Window->Links to bring up the Links panel which shows external images that are "linked" to in your artwork. From there you can relink, update the link (if the placeholder source image was updated), and even embed the link into your Illustrator file.