gistfile1.txt

//Save an image with a size constraint in its original folder; if quality restriction is met, resize longest dimension until criteria are met
var docRef = activeDocument;
var outputFolder = docRef.path;

NamesaveRef = new File(outputFolder + "/WM");
var NewfileRef = new File(NamesaveRef);

// quality/size constraints
var h = 2400; //new file height
var w = 2400; // new file width
var MaxSz = 97280; // max. 85Kb
var MinSz = 288; // min. 4in @72dpi
var Qlt = 100; // initial quality 100
var x = 5; // decreasing step
var Px = 72; //decreasing step in px once Qlt < 50

// Perform the first SaveForWeb Operation
ExpWeb(NewfileRef, Qlt);

//Check to see if document is wider than taller. Else will shorten height instead. 
if (activeDocument.width > activeDocument.height) 
{
    // Keep trying to save the file with max. Qlt, but under MaxSz    
  while (NewfileRef.length > MaxSz) {
		Qlt = Qlt - x;
		NewfileRef = new File(NewfileRef);
        NewfileRef.remove();
        ExpWeb(NewfileRef, Qlt); // Perform a new SaveForWeb Operation, with slightly lower Qlt
	}	
		if (Qlt <= 50); {	
				while (NewfileRef.length > MaxSz) {
				
				w = w - Px;			
				NewfileRef = new File(NewfileRef);
				NewfileRef.remove();
				NewfileRef.resizeImage(UnitValue(w,"px"),null,72,null);
					if (w <= MinSz) {
						alert("The file can't be saved with the desired size AND quality.");
						break;
					}	
				}
		
		}
}	
else {
    // Keep trying to save the file with max. Qlt, but under MaxSz    
	while (NewfileRef.length > MaxSz) {
		Qlt = Qlt - x;
		NewfileRef = new File(NewfileRef);
        NewfileRef.remove();
        ExpWeb(NewfileRef, Qlt); // Perform a new SaveForWeb Operation, with slightly lower Qlt
	}	
		if (Qlt <= 50); {	
				while (NewfileRef.length > MaxSz) {
				
				h = h - Px;			
				NewfileRef = new File(NewfileRef);
				NewfileRef.remove();
				NewfileRef.resizeImage(UnitValue, null,(h,"px"),72,null);
					if (h <= MinSz) {
						alert("The file can't be saved with the desired size AND quality.");
						break;
					}	
				}
		
		}
}

// close the original file without saving
activeDocument.close(SaveOptions.DONOTSAVECHANGES);
//docRef.resizeImage(UnitValue(w,"px"),null,72,null);
// SaveForWeb Export, with the desired constraints and parameters

function ExpWeb(FileNm, Qlt) {
    var options = new ExportOptionsSaveForWeb();
    options.quality = Qlt; // Start with highest quality (biggest file).
    options.format = SaveDocumentType.JPEG; // Save Format for the file
    docRef.exportDocument(File(FileNm), ExportType.SAVEFORWEB, options);
}