Ideas for better image replacement?

When I start building a slideshow I alway beginn by generously selecting potential images. These images are mostly unprocessed loRes exports from the original RAW-Files. Then I start composing the slideshow chapter by chapter placing the images on the timeline that fit the storyline and discarding the ones I don’t need. Only at the end I start editing the final set of images going back to the original RAW-Files and exporting HiRes JPEGs. By doing so I save a lot of time by not having to edit all potential pictures but only the ones I’ve decided to really use.

The problem is that there is no easy way to batch replace the images in the whole timeline. Even the images inside the package (content) can’t simply be overwritten because the file names are scrambled.

I know I can mark each image as a placeholder and then drag and drop the edited image to replace it, but that is an awfully time consuming progress and also a source of potential mistakes. Any suggestions or ideas how that could be accomplished easier?