to be on the safe side, you can type in the whole path of the image. Let's say your html file is in
http://www.uberleethost.com/welshboy/ and that your image is in
http://www.uberleethost.com/welshboy/IMAGES/.
With this you have two options:
1) (the one Supersonicdarky wrote)
<img src="IMAGES/Guy.JPG">
2) The whole URL, this works on all pages on all sites
<img src="http://www.uberleethost.com/welshboy/IMAGES/Guy.JPG">
/ 
