One approach to do this is to make all the images anchored frames, which makes them move like text (and with the text). Thus, if you insert a new picture, everything from there on out will be shifted forward to make space for the new image.
A relatively easy way to make an anchored frame is to import the image to the pasteboard (area outside the page), size it, then select the image’s containing box, switch to the text tool, select the insertion point in the text box and paste.
If you need captions for the images, you can make them in a separate text box (while still on the pasteboard), group it with the image and then copy the group as a whole, and paste into text as anchored image.
To make life easier, you could have a master set of pre-sized image boxes (and text boxes, if needed) on the pasteboard that you copy before importing images into them.
There may be complications if you are using different size images, as they won’t necessarily fit onto the new pages as they reflow.