Andrew. if the HTML page is in the WEB folder and you are calling for the image in the IMAGES folder use this <img src="images/mypic.jpg">
If the HTML is someplace NOT in the root folder then you will have to navigate to the images folder i.e. the HTML page in in a folder called WIDGET which is also in the WEB folder: <img src="../images/mypic.jpg"> I hope this helps.