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.