How do you overlap an image? Let me count the ways.
- Shakespeare
Um, kidding aside, there really are many ways to do that. None that I know of are purely HTML though. Perhaps the simplest is to put two images side by side and position the second one relatively to overlap the first using style:
<img src="1st.gif" width="50" height="50"><img src="2nd.gif" width="50" height="50" style="position:relative;left:-10px;">
That, for example would make two 50x50 images overlap by 10 pixels.