replacing Atahualpa header image

Hi, I hope someone can give me a little direction. I've read the threads regarding this topic and I'm still not sure what I'm doing wrong. All of this is new to me but I'm extremely anxious to learn.

I've gone to the files that hold the Alatualpa header images. I deleted what was the defaults and uploaded my own image (I have a custom header that I created in Photoshop and have saved it as a Jpeg). After what I thought was making the changes, I saved but the image is not showing up, it's just a blank area. I've read that the problem could be from some sort of cache add-on (really don't understand what exactly that is or how to find it and correct the issue).

Something, I'm curious about. I'm uploading images via ftp directly from my local folders, should I be uploading from my image library on Wordpress? If so, how do I navigate to this place? I've lurked around in every folder but can't seem to find it.

When I'm working on my blogs appearance and I click on "go to blog" my custom image shows up but it still doesn't show up when I go straight to www.straycatalley.com/blog Any clue? (It also shows up at www.straycatalley.com/blog/admin

I would appreciate any assistance.