Try this code<img src="c:/documents and settings/Username/my documents/my pictures/example.jpg">
Please check the extention of the image you are using(gif,png,jpg,bmp etc..) and make sure that the directory is typed correctly.I would suggest that you create a new folder and paste everything you are going to use in you page. This willsave you time becourse the will be no need to write the full name of the directory.Like this
<img src="example.jpg">