This example shows the effects of JPEG compression at various levels of quality. The first file is a GIF version of the original, requiring 258898 bytes of storage. The other files use "quality" factors of 100 (best) down to 5 (nearly the worst) and therefore require space in the range 326321 down to 9438 bytes.
Note: The original photo was taken by H. Rex Hartson and stored as a TIFF file. That was processed by Adobe Photoshop, and required 781300 bytes of storage. The TIFF file was converted to PNM format and then "cjpeg" was run to produce the JPEG files.