What is web safe (or Netscape) colors?
Upon the time when colors were limited in numbers but the web was evolving fast there was a scheme introduced that used only 216 colors, only 6 shades of red, 6 of green and 6 of blue. These shades were fixed to certain values that the older browsers supported, and until this day some still can not render more than these, believe me. So if you really like to be safe then you save your images using GIF and 6-6-6 palette type. Another benefit is that the file size may be drastically reduced without that much quality loss, hence I recommend you to always give it a try. An example: The Java installment of September, the ColorBox article, used a screen capture that originally looked as the upper image. It used 24-bit color depth and had a file size of 7,966 bytes using the GIF format. Trying to use JPG with 75% quality gave me 13,856 bytes in spite of using “Optimize entropy encoding” that further reduced the JPG file size about 3 kB (without this latter encoding the file size was about 15
