The Cabin in Sunrise

Visiting my girlfriend's family for early Christmas this past weekend, I woke up just after sunrise and started shooting. C&C is welcome!

For this first photo, I shot 3 exposures handheld using AE bracketing 0+-1.6. I was using my Canon 40D and Sigma DC 18-200mm lens.

Camera settings were: 18mm, f/3.5, ISO 200. Exposure times were 1/800s for the normal exposure, and 1/250s & 1/2500s for the two exposures that I blended.

I only blended the over and underexposures to make this HDR composite, I didn't use the normal (middle, 1/800s) exposure. I did some adjustments in PS CS3: Shadow/Highlights, USM for local contrast enhancement with 10,50,0, some leveling, and finally USM 200,0.3,3 for output sharpening just before saving to jpeg.

Embedded is a low-res copy, please click here for a fullsized JPEG, filesize: 8MB

Apologies for bumping my own thread, but after creating the smaller jpeg for posting here I have come up with a question for y'all.

I noticed that after reducing the image resolution, the smaller file is a much sharper image. On both the large image and the low res image I applied the same USM 200% 0.3 pixels 3 levels filter before saving to JPEG.

What causes the smaller image to appear sharper, and how can I get that crispness in my larger file?

Thanks.