The image i upload is not what is shown, it looks degraded somehow?

I created an image in photoshop, 300×250 @ 96dpi and 16bit Rgb, two colors. Looking at it on my screen it looks just how i want it, nice clean lines and all. I uploaded it to my self-hosted wordpress blog i am working on and now the image looks like it’s degraded. When you take a small image and stretch it to a bigger one or it’s been severly optimized. I’m saving as a .jpg with the highest quality setting. Any help great appreciated. Am i missing a toggle or checkbox somewhere?

fromateakdeck.com The image is the Unleashed Petography ad banner on the right that is black and white, you can see white pixels around the edges of the logo and lettering.

TIA Again

The page I need help with: [log in to see the link]