please expain us your problem in a better way; what are you trying to do?
I have several pictures in a layers of the "index" page, which is left on many pages in the project. Want to swap out images in the layer, and simultaneously update all pages that have this layer!
I think you should choose an other approach. Assuming your "index" page has all the object which you'll like to show on all the other pages: Save this page in the folder shared of your project and name it template or so.
Then make a new page (be sure to be back in your projects root again) and import this template page in your new page.
Importing can be done by clicking the green arrow in the left of your screen. There you can choose for Insert DHE file.
Now you will see the object of your template in your new page. Changing something in the template will also change the imported part of your new page. To see the changes you can reopen this new page or refresh the imported part by selecting the imported part and clicking the refresh button in its properties..