Calculate upload speed

If you want to test the upload speed I don't see why you would want to send this specific image.

I would rather send raw data.

Here is an example :

var http = new XMLHttpRequest();
var startTime, endTime;
var url = "script_that_whill_handle_post.php";
var myData = "d="; // the raw data you will send
for(var i = 0 ; i < 1022 ; i++) //if you want to send 1 kb (2 + 1022 bytes = 1024b = 1kb). change it the way you want
{
    myData += "k"; // add one byte of data;
}

http.open("POST", url, true);

http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
http.setRequestHeader("Content-length", myData .length);
http.setRequestHeader("Connection", "close");

http.onreadystatechange = function() {
    if(http.readyState == 4 && http.status == 200) {
        endTime = (new Date()).getTime();
        ShowData();
    }
}
startTime = (new Date()).getTime();
http.send(myData);

(Use the same showData function)

You could also send the data of the image instead of the letter "k" multiple times but it would need more code and I won't see any improvements doing this.

Hope it helped

For ajax uploads:

var lastNow = new Date().getTime();
var lastKBytes = 0;
var xhr = new window.XMLHttpRequest();
xhr.upload.addEventListener("progress", function(e) {
    if (e.lengthComputable) {
        var now = new Date().getTime();
        var bytes = e.loaded;
        var total = e.total;
        var percent = bytes / total * 100;
        var kbytes = bytes / 1024;
        var mbytes = kbytes / 1024;
        var uploadedkBytes = kbytes - lastKBytes;
        var elapsed = (now - lastNow) / 1000;
        var kbps =  elapsed ? uploadedkBytes / elapsed : 0 ;
        lastKBytes = kbytes;
        lastNow = now;
        console.log(mbytes.toFixed(2) + "MB (" + percent.toFixed(2) + "%) " + kbps.toFixed(2) + "KB/s");
    }
}, false);