[kube]

And if it's the category header image you're after, make a back up of dingbats_categorie.gif and rename it or something. Then upload your own image with the same filename.

Or similarly open up skin1/customer/categories.tpl and locate (should be near enough the last line)...

{ include file="menu.tpl" dingbats="dingbats_categorie.gif" menu_title=$lng.lbl_categories menu_content=$smarty.capture.menu cellpadding=$fc_cellpadding}

Upload your image to your /skin1/images/ folder and change the dingbats located in the code above, to dingbats="whatever-filename.jpg"

Hope this helps.