Script to select all images on artboard

var doc = app.activeDocument;
doc.layers.add().name = "Images";
doc.layers.add().name = "Linked Files";
doc.layers.add().name = "Other";
for (var i = 0; i < doc.pageItems.length; i++) {
    if (doc.pageItems[i].typename == "RasterItem") {
        move(doc.pageItems[i], doc.layers["Images"]);
    } else if (doc.pageItems[i].typename == "PlacedItem") {
        move(doc.pageItems[i], doc.layers["Linked Files"]);
    } else {
        move(doc.pageItems[i], doc.layers["Other"]);
    }
}
function move(what, where) {
    what.move(where, ElementPlacement.PLACEATEND);
}