I installed More Pics on a clean RC1. All is fine (show pictures on the front part) except that it doesnt show any pictures in the admin - it adds "catalog/admin/" to the address of the pictures (and flags, but not to buttons and folders' icon).
Here is one of the standard subcategory pictures addresses: "http://localhost/catalog/admin/catalog/images/subcategory_graphic_cards.gif". It also doesnt show the flags in the edit product page, but shows buttons and folder icons (http://localhost/catalog/admin/catalog/includes/languages/english/images/icon.gif).
Compared the categories with the MS2 and all the differences are added in my categories.php (RC1), so no problem in the transfer.