Pass Image Array to $.ajax

var imageArray= GetImage();

$.ajax({
            type: "POST",
            url: "Default.aspx/Save",
            data: "{htmlDiv:'" + htmlDiv + "',postData:'" + postData + "',ImageArray:'" + imageArray+ "'}",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function (result) {
                 alert('success');
            },
            error: function (ex) { return true; }
      });

function GetImage() {
    var canvas = document.getElementById("canvasTest");
    var context = canvas .getContext("2d");

    //return { index: 0, image: canvas .toDataURL() };
    var imageArray= [];

    imageArray[imageArray.length] = canvas .toDataURL()

    return canvas ;
}