Quoting WISE site where an annotated version of the image can be seen: "This is a mosaic of the images covering the entire sky as observed by the Wide-field Infrared Survey Explorer (WISE), part of its All-Sky Data Release. In this mosaic, the Milky Way Galaxy runs horizontally across this map. The Milky Way is shaped like a disk and the Solar System is located in that disk about two-thirds of the way out from the center.

[W]e see the Milky Way as a band running through the sky. As we look toward the center of the Galaxy we are looking through more of the disk than when we are looking at large angles away from the center, and you can see a noticeable increase in stars (colored blue-green) toward the center of the image. Three of the four wavelengths surveyed by WISE were used to create this image. The colors used in this image represent specific wavelengths of infrared light. Cyan (blue-green) represents light emitted predominantly from stars and galaxies at a wavelength of 3.4 microns. Green and red represent light mostly emitted by dust at 12 and 22 microns, respectively."

The size of the uploaded image is 190 megapixels. Original JPEG equirectangular image can be downloaded here.

Image Credit: NASA/JPL-Caltech/WISE Team (this image is in public domain).

I've prepared different version of the image to my blog at pallopanoraama.blogspot.com which contains overlaid info bubbles helping navigating the image and a visible light version of the sky for comparison.