An image drop down menu that links each image to a page?

so basically the title explains most of it but would like to be able to have an image which when you click it a drop down menu of images will come up where each image would link to a specific page

Would also be good if the image links could be picked up by google you know the whole crawlability thing

if anyone could help would appreciate it

 

Prob should add that my pages are html and not wanting to change them to another extension