Department of Electrical Engineering and Computer Science Department of Mechanical Engineering 6.050J/2.110J – Information, Entropy and Computation – Spring 2014

JPEG Demonstration

The JPEG demonstration on this page shows the tradeoff between file size and image quality for JPEG compression.
These images are scaled to fit on this page. Click on any image to view or download it at full size.

	Original	Excellent Quality	Good Quality	Fair Quality	Poor Quality
Format	TIFF	JPEG	JPEG	JPEG	JPEG
Compressed?	no	yes	yes	yes	yes
Image width	1200 pixels	1200 pixels	1200 pixels	1200 pixels	1200 pixels
Image height	1400 pixels	1400 pixels	1400 pixels	1400 pixels	1400 pixels
File size	5,044,532 bytes	1,128,080 bytes	103,690 bytes	52,437 bytes	37,664 bytes
Compression ratio		4.47	48.65	96.20	133.94
Quality scale		100%	67%	20%	5%
Display width on this page	99 pixels	99 pixels	99 pixels	99 pixels	99 pixels
Display height on this page	116 pixels	116 pixels	116 pixels	116 pixels	116 pixels

Note that even with compression ratios as large as 100 the image quality is quite acceptable for many purposes. Most quality differences can only be seen from the full-size compressed images (for example, look at the rendering of the hair, especially the wisp near the left ear). There are slight color variations that were not caused by the compression.

Compression was performed in GraphicConverter, version 8.7.1.  Files were saved without metadata. Image quality was set using a sliding quality scale with default settings for most options.

The image used in this demonstration was cropped from a photograph taken at a live concert of The Spectrum Singers, a few minutes after the photograph below.

The Spectrum Singers in concert, Cambridge, MA, May 18, 2013.