The Herschel-ATLAS Data Release 2, Paper I. Submillimeter and
  Far-infrared Images of the South and North Galactic Poles: The Largest
  Herschel Survey of the Extragalactic Sky
  We present the largest submillimeter images that have been made of the
extragalactic sky. The Herschel Astrophysical Terahertz Large Area Survey
(H-ATLAS) is a survey of 660 deg$^2$ with the PACS and SPIRE cameras in five
photometric bands: 100, 160, 250, 350, and 500{\mu}m. In this paper we present
the images from our two largest fields which account for ~75% of the survey.
The first field is 180.1 deg$^2$ in size centered on the North Galactic Pole
(NGP) and the second field is 317.6 deg$^2$ in size centered on the South
Galactic Pole. The NGP field serendipitously contains the Coma cluster. Over
most (~80%) of the images, the pixel noise, including both instrumental noise
and confusion noise, is approximately 3.6, and 3.5 mJy/pix at 100 and
160{\mu}m, and 11.0, 11.1 and 12.3 mJy/beam at 250, 350 and 500{\mu}m,
respectively, but reaches lower values in some parts of the images. If a
matched filter is applied to optimize point-source detection, our total
1{\sigma} map sensitivity is 5.7, 6.0, and 7.3 mJy at 250, 350, and 500{\mu}m,
respectively. We describe the results of an investigation of the noise
properties of the images. We make the most precise estimate of confusion in
SPIRE maps to date finding values of 3.12+/-0.07, 4.13+/-0.02 and 4.45+/-0.04
mJy/beam at 250, 350, and 500{\mu}m in our un-convolved maps. For PACS we find
an estimate of the confusion noise in our fast-parallel observations of 4.23
and 4.62 mJy/beam at 100 and 160{\mu}m. Finally, we give recipes for using
these images to carry out photometry, both for unresolved and extended sources.
