I have created a gallery for every user. I would now like to alter the view so that one of the images is a medium size and the other images are thumb nail size. I know you can adjust the layout in a view but I am not sure how to change the size of one image and keep the others as the default thumbnail.
Check out the View Nodes Split module. This module allows site administrators or builders to have a different view mode for the first nodes of a view result.
You can also use the 'Views Attachment' feature in views to Display the first node as you wish, then attach the rest of them to the first. Just make sure you offset your attached view by 1.