This is way too small, for starters. You are allowed a 640 pixel maximum. I suggest you take advantage of it next time. As for the challenge, I don't understand what is being advertised. Tourism? The blue in the clouds and the mountains looks bizarrely unreal.
Nice colors and contrast. Good choice for placement of the horizon. This would be more compelling if the image were larger. As it is, I can't see enough of the detail.
Looks like a nice photo, but the size is really a lot smaller than the other photos. Makes it seem like a lesser photo as the detail is harder to appreciate. I'd like it bigger.
Image is pretty small / hard to see, and I cannot see how this fits into the advertisement challenge.
If I'm wrong, private e-mail me and let me know.
Regards,