Wanted: Bridge or Photoshop script for taking a camera raw "snapshot"

Question

Hello,
i am looking for a way to create a "snapshot" in the xmp data of raw image files, like you do in camera raw's last tab "snapshots".
I can do copy&paste programming.
Here is a script that changes a certain value on a selection of image files. I  can take this as a starting point to work  in the xmp data in a selection of files. But what would a function to create a snapshot be?
#target bridge    if( BridgeTalk.appName == "bridge" ) {
setExposure = MenuElement.create("command", "Set Average Exposures", "at the end of Tools","exp");
setExposure.onSelect = function () {
var d=app.document;
d.deselectAll();
var sels = d.getSelection("cr2,crw,nef,mos,orf");
var noOfFiles =sels.length;
var diff = (3.25 / (noOfFiles-1));
var exp = 1.25;
var exp2=exp;
for(var a = 0;a<noOfFiles;a++){
    exp2 = exp - (diff*(a)).toFixed(3);
    var file = new File(sels[a].spec.toString().replace(/\....$/,'.xmp'));
    setExposure( file, exp2 )
app.document.chooseMenuItem('PurgeCache');
function setExposure( file, expose ){
     file.open('r');
     file.encoding = "UTF8";
     file.lineFeed = "unix";
     file.open("r", "TEXT", "????");
     var xmpStr = file.read();
     file.close();
     if (ExternalObject.AdobeXMPScript == undefined) ExternalObject.AdobeXMPScript = new ExternalObject("lib:AdobeXMPScript");
     var xmp = new XMPMeta( xmpStr );
     xmp.setProperty( XMPConst.NS_CAMERA_RAW, "Exposure", Number(expose) );
     file.open('w');
     file.encoding = "UTF8";
     file.lineFeed = "unix";
     file.write( xmp.serialize() );
     file.close();
regards,
Stephan Möbius

Answer 1

Hi Stephan,
Nice to hear from you.
I would first like to tell my understanding your problem clearly.
What I understood is that you want create a “snapshot” (thumbnail) of a camera raw file and put it inside the XMP Packet.
You have got a script which can update XMP of file, on selecting a menu item.
You want to know how to create a “snapshot” of a raw file so that you can insert it in XMP using the script.
Workflow will be, you will open a camera raw file, select some menu item, and on doing that the snapshot will be updated in the XMP.
Is this understanding correct?
If not please clarify the workflow and the problem you are facing.
Thanks,
Amit