1. thats a partial error so cant comment fully but try setting your processor to gd2 and see if uploads work as your error would indicate some sort of mogrify issue.
2. Your electing to break the width with the settings your using. For one on fixed width pages you probally dont want to use a sidebar on the showphoto pages. Next your next previous images you have turned to top which means its going to print 7 images horizontally across the page and what makes it worse if your using a thumbnail overlay which makes each thumbnail 167 pixels wide.
a. try setting a different thumbnail overlay
b. try turning the next previous on off top left right bottom and 1 rows etc all through the settings in showphoto in admin for that feature.
It is all about the right combination of features when restricting page width. You will never be able to squeeze 1400 pixel wide of info in a 1024 pixel space without scrolling.