PyMOL can read and write PNG format image files. PNG is a lossless compressed image format ideally suited for preservation of high-quality PyMOL renderings.

Writing is done with either save or png. The png command provides the ability to set resolution explicitly within the file:

# 4 inches x 600 dpi = a 2400 pixel image

ray 2400

# now save with a DPI value in the output file

png my600dpiImage, dpi=600

PyMOL can also load PNG files for transient display inside PyMOL using load_png.