The LOFAR Two-metre Sky Survey (LoTSS) is described in Shimwell et al. 2017 and will eventually map the entire Northern sky. Each of the 3170 pointings will be observed for 8hrs, which, at most declinations, is sufficient to produce ~5arcsec resolution images with a sensitivity of ~0.1mJy/beam and accomplish the main scientific aims of the survey. Due to the compact core and long baselines of LOFAR, the images provide excellent sensitivity to both compact and highly extended emission. The preliminary images we have released are significantly more sensitive than those produced by any existing large-area low-frequency survey. In excess of 35,000 sources are detected in the images that cover an area of over 350 square degrees, have a resolution of 25arcsec, and typical noise levels of less than 0.5mJy/beam.