Phonegap / Cordova File Transfer Upload Image as Base64 String not working in ios

I am working on loading image as base64 image stream from phonegap / cordova app, it works fine on android but doesn't work in ios, however in ios it works when the image is png / jpg but when it's base64 the image stream its not working please someone can help me with the same.

Here is my code for the same,

var options = new FileUploadOptions();
    options.fileKey = "file";   
    options.fileName = "test.jpg";
    options.mimeType = "image/jpeg";    
    options.chunkedMode = false;

     options.params = {
                "key": "test.jpg",
                "AWSAccessKeyId": awsKey,
                "acl": acl,
                "policy": policyBase64,
                "signature": signature,
                "Content-Type": ""
            };

    var ft = new FileTransfer();
    ft.upload(imageURI, s3URI + "",
            win, fail, options);
}
function win(r) {
    console.log("Code = " + r.responseCode);
    console.log("Response = " + r.response);
    console.log("Sent = " + r.bytesSent);
    alert(r.response);
}
function fail(error) {
    alert("An error has occurred: Code = " + error.code);
}