Set Image Using JavaScript

//Hook this method to the "OnChange" event of "creditlimit" field
     function SetImage()
     {
 debugger;
    var productId = Xrm.Page.data.entity.getId();
    var productName = Xrm.Page.getAttribute("name").getValue();

    if (productName != null)
    {

        //retrieve image onecoinpile.jpg and update product record "EntityImage" attribute
        this.UpdateproductRecordWithNewImage(productId, "new_BurgerGift.jpg");

    }
}

 function UpdateproductRecordWithNewImage(productId, webResourceName)
 {

 debugger;
    this.GetImageWebResource
    (
        productId,
        webResourceName,
        this.UpdateProductRecord
    );

}



function GetImageWebResource(productId, imageName, successCallback)
{
   debugger;

    //OData URI to get address information from parent account record
    var oDataURI = Xrm.Page.context.getClientUrl()
        + "/XRMServices/2011/OrganizationData.svc/"
        + "WebResourceSet"
        + "?$filter="
        + "Name eq '" + imageName + "'"
        + "&$select=Name,Content";


    //Synchronous XMLHttpRequest to retrieve account record
    var req = new XMLHttpRequest();
    req.open("GET", encodeURI(oDataURI), false);
    req.setRequestHeader("Accept", "application/json");
    req.setRequestHeader("Content-Type", "application/json; charset=utf-8");
    req.onreadystatechange = function ()
    {
        debugger;
        if (this.readyState == 4 /* complete */)
        {
            req.onreadystatechange = null; //avoids memory leaks
            if (this.status == 200)
            {
                //parse the response string as a JSON object into the successCallback method.
                successCallback(productId, JSON.parse(this.responseText).d);
            }
            else
            {
               alert("error");
                var errorMsg1 = "GetImageWebResource Error: cannot retrieve image with name = " + imageName + ".";
                //display a non-blocking alert dialog
                Xrm.Utility.alertDialog(errorMsg1, function () { });
            }
        }
    };
    req.send();
}


 function UpdateProductRecord(recordId, webResource)
 {
   debugger;


 try{
    //var product = {EntityImage:""};
    var product = webResource.results[0].Content; //byte[] content of the web resource

    alert(product);

    var jsonproduct= JSON.stringify(product);
    alert(jsonproduct);
   }catch(ex){
      console.log(ex);
   }

    //OData URI
    var oDataURI = Xrm.Page.context.getClientUrl()
        + "/XRMServices/2011/OrganizationData.svc/"
        + "productSet(guid'" + recordId + "')";
    alert(oDataURI);
    //Synchronous post
    var req = new XMLHttpRequest();
    req.open("POST", encodeURI(oDataURI), false);
    req.setRequestHeader("Accept", "application/json");
    req.setRequestHeader("Content-Type", "application/json; charset=utf-8");
    req.setRequestHeader("X-HTTP-Method", "MERGE");
    req.onreadystatechange = function ()
    {
        debugger;
        if (this.readyState == 4 /* complete */)
        {
            req.onreadystatechange = null;
            if (this.status == 204 || this.status == 1223)
            {
                //reloads the product record
                window.location.reload(false);
            }
            else
            {
               alert("error");
                var errorMsg2 = "UpdateProductRecord Error: Cannot update product record with productId = " + recordId + ".";
                //display a non-blocking alert dialog
                Xrm.Utility.alertDialog(errorMsg2, function () { });
            }
        }
    };
    req.send(jsonproduct);
    alert(jsonproduct);
}