Let's start with the obvious question --- do you really need all the disk space and bandwidth you claim? 1 TB/month is a LOT of bandwidth for any site ... even for an image gallery ... even if it is within the top 50,000 on Alexa. If I may ask, what is the URL of this site?
I think you'll be able to narrow-in on a good selection of options once you ask yourself exactly what kind of resources you need.
I'm using hostgator for my gallery site.Not too bad until now.But maybe i'm still planning to move to others in the middle of the year.My young database driven site most of time load slow.I don't know it's the problem of wordpress (i use wp for publishing photos) or hostgator.