[ Branched ] How to relink all embedded images under clipping mask

here you go, you still need to select the clipped images (the images themselves, not the mask). You can do that with the group selection tool

//#target Illustrator
 
// script.name = relinkAllSelected.jsx;
// script.description = relinks all selected placed images at once;
// script.required = select at least one linked image before running;
// script.parent = CarlosCanto // 7/12/11; 05/12/19 updated for CC2019
// script.elegant = false;
 
var idoc = app.activeDocument;
sel = idoc.selection;
if (sel.length>0) {
      var file = File.openDialog ("open file");
      file = new File(file.fsName.replace("file://","")); // Mac OS Lion fix by John Hawkinson
      
      for (i=0 ; i<sel.length ; i++ ) {
           if (sel[i].typename == "PlacedItem") {
                var iplaced = sel[i];
                iplaced.file = file;
             }
           if (sel[i].typename == "RasterItem") {
                var iplaced = idoc.placedItems.add();
                iplaced.file = file;
                
                iplaced.move(sel[i], ElementPlacement.PLACEBEFORE);

                h = sel[i].height;
                w = sel[i].width;
                x2 = sel[i].left;
                y2 = sel[i].top;

                iplaced.position = [x2+w/2-iplaced.width/2, y2-h/2+iplaced.height/2];
                
                sel[i].remove();
             }
       }
}
else
     {
          alert("select at least one placed item before running");
     }