This is a NASA image from the lower-left edge of Pluto’s 'Heart' more technically called the Tombaugh Regio (Tombaugh Region). The peaks are estimated to be approximately one-half to one mile (1–1.5km) in height, or about the same scale as the Appalachian Mountains.
Sputnik Planum is believed to be relatively young in geological terms, less than 100 million years old or so, while the darker region is most likely billions of years old.
The image was acquired by the Long Range Reconnaissance Imager (LORRI) on July 14 from a distance of 48,000 miles (77,000 kilometers) and sent back to Earth on July 20. Features as small as a half-mile (1 kilometer) across are visible. The names of features on Pluto have all been given on an informal basis by the New Horizons team.
Image Credit: NASA/JHUAPL/SWRI
And wow - look at this ...
Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Go look at more images at https://www.nasa.gov/feature/new-pluto-images-from-nasa-s-new-horizons-it-s-complicated