What does it mean to "downsize the images to...."

Deeve wrote:

Hi, I've seen some reference downsizing the image taken by the DSC-HX200 to reduce image noise. The below quote I pulled from the review here. Is the author talking about changing the image megapixel capture size in the camera settings or resaving the photos at a lower resolution with an editing program?

"Image sharpness varies greatly. Some things are nice and sharp, while fine details get smudged, a victim of the heavy noise reduction being applied to these 18 Megapixel images (even at ISO 100). That said, if you downsize the images to match the resolution of similar super zooms, the HX200V comes off looking pretty good."

thanks!

Dave