How to reload/refresh an element(image) in jQuery
It sounds like it's your browser caching the image (which I now notice you wrote in your question). You can force the browser to reload the image by passing an extra variable like so:
d = new Date();
$("#myimg").attr("src", "/myimg.jpg?"+d.getTime());
It's probably not the best way, but I've solved this problem in the past by simply appending a timestamp to the image URL using JavaScript:
$("#myimg").attr("src", "/myimg.jpg?timestamp=" + new Date().getTime());
Next time it loads, the timestamp is set to the current time and the URL is different, so the browser does a GET for the image instead of using the cached version.