detect image change event

Question

How do I detect the change if I have mouseover a thumbnail image, the main image will replace with the thumbnail, I believe onLoad() does only fire once.

Answer 1

If i understand you correctly :

Use onmouseover. onload is a document event handler.

<img src="images/oldImage.jpg" onmouseover="this.src='images/newImage.jpg'; alert("Mouse detected over thumbnail.  New fullsize Image Loaded!");>