Web Safe Colour

To set the consistent color across on several different operating system needs web safe clor. The value 216 comes from 256 possible colors available in a 8 bit palette such as those used for GIF images minus 40 unique system colors that the various operating system use.

Lossy VS Lossyless Compression

The term lossy and lossyless refer to the type of compression that used to reduce the size by removing image information such as unneeded colors or details. Lossyless compression does not remove any image information, but compresses the image by looking for sections of similar colour that repeat within the image. An image compressed losslessy can be converted again to its original state. A lossy compressed image can not.

Resolution settings

one of the important aspect while working for web graphics is DPI settings. The maximum resolution that is possible for computer moniter is 72 DPI .All web graphics can be saved at this settings to ensure the best possible resolution.

Save for web

The created image or art need to be optimized before published on to web. For this save for web command is used .choose -file -save web to oen the save for web dialog window.It has set tools to manipulate the sliced images. The slice select tool used to divide the images into individual pieces. Each slice can have it's own format.

Web file format for pixel images

There are three commonly used file format for web are GIF,JPEG, PNG .Each format has its advantages and disadvantages

GIF : The GIF image format is perhaps the most popular and common graphic format used on the web.This format includes a 256 color palette and features such as single color transparency, interlacing, and animation capability. GIF images also include automatic lossless compression.

JPEG : The JPEG images format is also used quite heavily on the web. It supports 24 bit color and features such as progressive enhancement, which enables the image to be displayed as it downloads. JPEG images can be compressed using a lossy compression algorithm. This algorithm can reduce the original file size as much as 1/10 the size of the JPEG format enable you to set the amout of compression to use.

PNG

The PNG image format is fairly new and offers 36 bit color including alpha channel support. This format is going popularity, but is not supported on old browsers.The PNG format offers lossless compression.This format also comes in two flavours PNG 8
and which supports 256 colors and PNG 24 which supports a full 16.7 million colors.