Missing Large Photo After Server Migration

I am in the process of a server migration, database and files have been moved over but I am having an issue with the large image missing. from a user interface, the galleries show the grid view fine but when I click on an image I get a blank window. If i look in the photo section where the gallery is created and click on an image, I do see the larger photo. It also looks like like i have files for the "large", "mini", "small", "original" and "th" so not sure what is missing. Please advise
t Sean

I'm sure it is not missing, you probably have a server error causing the window not to load.

If you want me to look into the server error You can email me the following 

• 1) The link / URL to your Sytist admin (where you log into your Sytist admin).
• 2) The admin username and password (or create me an admin account by clicking Admins in the upper right corner of the admin pages).