How to get the categories archieves with the thumnail images in wordpress?

I need to 开发者_运维技巧show the thumbnail images on the category pages.,but the condition is the thumbnail images are only achieved posts....

If there any possible to do this on wordpress.,please guide me.,or give the codes for wordpress...

Thanks in advance.,

---

try reading this one http://codex.wordpress.org/Function_Reference/wp_get_archives