How Do You Setup A Viral Picture Site & Not Quickly Overload The Host Servers With Viral Pics!

RackSpace.com is one place to look for pricing, they have a very good content delivery network from my experience. If you dont want to use one right off the bat then thats totally up to you. Heck get a cheap hosting account with host gator and just monitor traffic and upgrade as you go a long.

I would just make sure the images are exact sizes, so if you have a thumbnail of 100x100 make sure its actually 100x100 instead of just resizing a huge image down to 100x100. Will help with page loading etc. Also you can do something like create a subdomain to request images from, for example:

mysite.com
img.mysite.com

By default browsers have 2-4 pipes open to download content, request the images from a sub domain and it will have more pipes open to download. Caching is another way of helping with load times. Minifying can help with the overall page size and load size, so instead of having lets say 4 css files being downloaded have it all in one file. Make sure css is in the header and either put the js after the css or at the bottom of the page, that way js loads last while the page loads. Making it look like its loading fast, progressive loading. There is a lot you can do to help with optimizing speed, you could also use server side caching such as memcache if your using php.

What pictures are you going to upload and hope that they go viral? If they actually do go viral you will need to make sure that you own the photos (or have the rights to post them) if you're planning on monetizing them. Making money off of other people's photos makes photographers VERY angry!