Find unwanted duplicate photos

This is a bit crude - just trying to see if it works for you

It will create a text file on your desktop listing the images that are duplicated and what pages they are on

var allLinks = app.activeDocument.links;

var imageLinks = {};

for (var i = 0; i < allLinks.length; i++) {
  var linkName = allLinks[i].name;
  var parentObj = allLinks[i].parent;
  var pageNum = parentObj.parentPage.name;
  if (!imageLinks[linkName]) {
    imageLinks[linkName] = [pageNum];
  } else {
    imageLinks[linkName].push(pageNum);
  }
}


var file = new File("~/Desktop/image_links.txt");


file.open("w");

for (var linkName in imageLinks) {
  if (imageLinks[linkName].length > 1) {
    file.writeln(linkName + ': Pages ' + imageLinks[linkName].join(', '));
  } else {
    file.writeln(linkName);
  }
}

file.close();

alert('Image links have been saved to the file "image_links.txt" on your desktop.');