there's an useful article in the "Tips & Tricks" Section in the old (deprecated) documentation: http://ez.no/products/ez_publish/documentation/customization/tips_tricks/editing_creating_and_removing_content_from_the_user_page
But to give you specific help, you should describe your intentions more clearly, as there are some cliffs you need to keep in mind.
Do you want your users to have their own "album folders" or just one big <i>picdump</i>?
Depends on where you want the button to be displayed....
At first you need to edit the user roles and give the user the right to create images. Then take a look at the attribute_view_gui within the documentation and create your own edit template.