relink images with different names

Do you have the original links, before they were renamed? Because it is easier to fix the file names and relink in InDesign at the same time, which is quite easy to do in script. If you don't have the originally named files and have changed all the names, I'm afraid it might be a manual process to relink, unless there is a clearly defined method used to rename the files, in which case a script could be devised to duplicate the method used to figure out name changes, and by that, fetch the new file name and relink. That's a little more work.

But if you do have the files as originally named, below is an example of a simple script that could be modified easily for your purpose. This script is for making all links web/ebook legal (all lowercase and all spaces/punctuation changed to dash character). This particular script is so my ebook conversions or other export to HTML doesn't have links that end up as URLs looking like "This%20Is%20The%File%20Name.jpg". Instead, the script converts the actual file names and relinks in InDesign so the same example ends up "this-is-the-file-name.jpg"

The area to pay attention to is "FILE NAME TRANSFORMATIONS". This area is where names are changed. Code before and after are to collect links and update them. This area you could modify to achieve the name changes you desire, whatever it may be. Just be careful -- this renames files on disk. Make a backup copy of files before trying it. If something goes wrong, the script could leave you with a folder full of screwed up file names. Use with care.

/*
Links Rename Web or Ebook
Copyright 2019 William Campbell
All Rights Reserved
https://www.marspremedia.com/contact
Permission to use, copy, modify, and/or distribute this software
for any purpose with or without fee is hereby granted.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#target indesign
(function () {
    var doc;
    var ext;
    var file;
    var i;
    var link;
    var name;
    if(!app.documents.length) {
        alert("Open a document.");
        return;
    }
    doc = app.activeDocument;
    if (!confirm("WARNING!\nFiles on disk will be renamed and this cannot be undone. Make backup copies of files before proceeding. Are you sure you want to continue?", true)) {
        return;
    };
    progress(doc.links.length);
    for (i = 0; i < doc.links.length; i++) {
        link = doc.links;
        progress.message(link.name);
        file = new File(link.filePath);
        name = link.name.replace(/.[^.]+$/, "");
        ext = link.name.replace(/^.*\./, "");
        // FILE NAME TRANSFORMATIONS
        // Make lowercase.
        name = name.toLowerCase();
        ext = ext.toLowerCase();
        // Replace punctuation with dash.
        name = name.replace(/[ ~`@#$%\^&\*()_=:;,\."'_~+<>\/\?\{\}\[\]\|\\]/g, "-");
        // Delete any leading dashes.
        name = name.replace(/^-/g, "");
        // Delete any leading underscores.
        name = name.replace(/^_/g, "");
        // Reduce double dashes to one.
        name = name.replace(/--/g, "-");
        // END FILE NAME TRANSFORMATIONS
        if (file.exists) {
        // Rename the file on disk.
            file.rename(name + "." + ext);
            // Then relink to renamed file and update.
            link.relink(file);
            link.update();
        }
        progress.increment();
    }
    progress.close();
    alert("Links successfully renamed and relinked.");
    function progress(steps) {
        var b;
        var t;
        var w;
        w = new Window("palette", "Progress", undefined, {closeButton: false});
        t = w.add("statictext");
        t.preferredSize = [450, -1]; // 450 pixels wide, default height.
        if (steps) {
            b = w.add("progressbar", undefined, 0, steps);
            b.preferredSize = [450, -1]; // 450 pixels wide, default height.
        }
        progress.close = function () {
            w.close();
        };
        progress.increment = function () {
            b.value++;
        };
        progress.message = function (message) {
            t.text = message;
        };
        w.show();
    }
})();

You could use this script written by Kasyan
Batch Rename and Relink

Hi Mathieu,

Try the following code and see if it works for your needs. I have modified the correct answer from the thread you posted.

var 
  sourceFolder = Folder.selectDialog("Show me a source folder"), 
  mLinks = app.activeDocument.links.everyItem().getElements(), 
  cLink, cFile; 
while ( cLink = mLinks.pop() )
{ 
  //Get the number in this fileName
  var num = cLink.name.match(/(\d+).*/)[1]
  var dest = File(sourceFolder.getFiles(num+"*"))
  cLink.relink(dest); 
}

-Manan