WHY 255? WHY 255? 28 = 256. THE VALUES THAT CAN BE WRITTEN USING 8 DECIMAL DIGITS RANGE FROM 0 TO 99,999,999 (=108 DIFFERENT VALUES). 99,999,999 = 9x107 + 9x106 + ... + 9x101 + 9x100 THE VALUES THAT CAN BE WRITTEN USING 8 BINARY DIGITS (BITS) RANGE FROM 0 TO 255 (=28 DIFFERENT VALUES). IN BASE 2: 11,111,111 = 1x27 + 1x26 + ... + 1x21 + 1x20

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This page is part of a section of lecture slides related to " Why GIF? Why JPEG? " within the topic "Using and Understanding Digital Images". Other slides within this section and other sections of slides for the topic "Using and Understanding Digital Images" can be accessed using the links below. Basics of HTML Image Tags Images Digital Images DIGITAL IMAGES PAINT BY NUMBER DIVIDING INTO PIXELS SAMPLING WITHIN PIXELS PIXEL RESOLUTION Why GIF? Why JPEG? "RGB" COLOR WHY 255? 24-BIT COLOR A STATISTICAL ANALYSIS OF "GREEN EGGS AND HAM" KEEPING THE DIGITS IN DIGITAL LOW-FAT EGGS AND HAM 8-BIT COLOR 8-BIT VS. 24-BIT "LOSSLESS" COMPRESSION TECHNIQUES "LOSSY" COMPRESSION HTML Color and Image Options SNOW "FFFFFF" AND BASIC "000000" HTML COLOR ATTRIBUTES OPTIONAL ESSENTIALS VERTICAL IMAGE ALIGNMENT HORIZONTAL IMAGE ALIGNMENT LINE BREAKS