The PNG Guide is an eBook based on Greg Roelofs' book, originally published by O'Reilly.

Color Insert: JPEG Compression

Figure C-3

Figure C-3: Effects of JPEG compression on sharp-edged features. In the upper half, note the regions of darker blue, the lighter echos around the white text, and the faint pinkish areas (for example, in the curve of the ``P''); the lower half has numerous dark echos around the text, bands of yellow above and below it, and very dark spots in some of the letters (particularly the ``s''). Even at a very low quality setting (for emphasis), the JPEG is three times as big as the completely lossless PNG version.

Last Update: 2010-Nov-26