Just been hand crafting some ePub's, I have a Sony Touch PRS-600 so can cope with clickable things within the Book.

The only type of link that appears to work is:
<a href="Page2">Page 2</a>

Buttons do not work:
<button type="button">Click Me!</button>

Hyperlink Images do not work:
<a href="Page2"><img src="Page2.jpg" alt="Page 2" /></a>
(Well the link line appears below the image which is clickable!)

Image maps do not work:
<DIV ALIGN=CENTER>

<MAP NAME="map1">
<AREA
HREF="contacts.html" ALT="Contacts" TITLE="Contacts"
SHAPE=RECT COORDS="6,116,97,184">
<AREA
HREF="products.html" ALT="Products" TITLE="Products"
SHAPE=CIRCLE COORDS="251,143,47">
<AREA
HREF="new.html" ALT="New!" TITLE="New!"
SHAPE=POLY COORDS="150,217, 190,257, 150,297,110,257">
</MAP>

<IMG SRC="testmap.gif"
ALT="map of GH site" BORDER=0 WIDTH=300 HEIGHT=300
USEMAP="#map1"><BR>

[ <A HREF="contacts.html" ALT="Contacts">Contacts</A> ]
[ <A HREF="products.html" ALT="Products">Products</A> ]
[ <A HREF="new.html" ALT="New!">New!</A> ]
</DIV>

The only idea I have had is to either:
1. Create Large font Hyperlinks
2. Create three Hyperlinks stacked above each other to gve a larger hit area.

:help: Does anyone know of any techniques that allow Images to be clicked?

Clearly this is not possible with ePub's.

However it is possible within PDF's (http://www.mobileread.com/forums/showthread.php?t=58645)

The <button> element is not supported by the ePUB spec (http://www.idpf.org/2007/ops/OPS_2.0_final_spec.html), but image maps and simple linked images should work, if they don't it's Sony's/ADE's fault.

but image maps and simple linked images should work

Yes you are right, I have seen linked images work, but not on the Sony PRS 600 Device.