Changing src attribute of IMG element using QWebElement API has no (visual) effect

After setting new src attribute of IMG element (QWebElement::setAttribute("src", "http://some.url.com/image.jpg")) element is not updated and shows original image.

Expected results:
IMG element should be reloaded and show image from specified URL.

Actual results:
IMG element still displays previous image from original URL but QWebElement::attribute("src") returns new URL.