what you want can be done super easily. Just declare a variable with the name of your first image, and put it where you want. Then make a button, and onclick, change the image's src.
You can see a working example of this on my webpage at www.windows-addict.com/index.htm?mind , in the down right-corner.
<img id="image" src="picture1.jpg" width="400" height="400">
<img src="button.png" onclick="document.getElementById('image').src="picture2.jpg">
You can put more images with a variable-name (like i=1, imagename='picture'+i+'.jpg' and then increase I with click, etc.) If this is what you want and need more advice, I'm happy to help.