Compresses the image using JPEG compression.
JPEG compression can be used on RGB, Grayscale, CMYK or
Separation images. It offers high compression levels for continuous
tone images like photographs. However it is a lossy method which
means that the quality of the compressed image will not be as good
as the uncompressed image.
The quality of the compression can range from zero (lowest
quality, highest compression) to 100 (highest quality, lowest
compression). A good generic value is 75.