Just to make sure proper credit is given, the header image on my blog is one I made using original images from NASA and ESA.
The sunrise/set image is from NASA, available on the Marshall Spaceflight Center’s Flickr page (image ISS021E031766). The nebula is the Cocoon Nebula (aka IC5246), as seen by Herschel, specifically by the PACS camera as part of the Gould Belt Survey.