Sidebar at the bottom of blog and images not resizing

I am very new at using/editing WordPress. However, I am having a problem that cannot be fixed with my amount of knowledge. I am using the Modularity lite theme and have done extremely minimal editing to this theme. The only change that I have made is decrease the sidebar size under screen.css. I successfully did this in a test environment. Any help in this matter would be great.

Also, I am trying to link large photos from my Flickr page (as I am a photographer). They will not re-size to the width of my blog: 750px. All images are owned by me. http://www.flickr/photos/btruxell/

My website link is http://www.somethinghdr.com