ò Different File Formats!

[color blue]What file format should I use?[/color]

There are many file formats, but I will stick to the most commonly used ones.

When creating pictures for the web, you should only use either .gif or .jpg file formats.

The different files:

.BMP
ò pronounced B-M-P or bitmap
ò these files are Windows based
ò they include 1-24 bit depth
ò 4 and 8 bit images are compressed using lossless compression
ò 24 bit images are not compressed

.GIF
ò stands for Graphics Interchange Format
ò these are 1 or 8 bit files typically used for the web
ò they are small in size, and allow for fast downloads
ò they support animations, interlacing, and transparencies
ò they are best used for clip art/cartoon style graphics
ò A GIF's color palette is limited to a maximum of 256 colors.
ò Avoid using GIF's for images with complex, subtle gradations of color.
ò The GIF file format uses lossless compression to keep file sizes as small as possible.

.JPEG (.JPG)
ò stands for Joint Photographic Experts Group
ò JPEG's are 24 bit colour images and are typically used on the web
ò JPEG files are the best choice for photographs and other images with continuous-tone color gradations.
ò The JPEG format was developed to reduce the file size of photographic images while maintaining quality.
ò JPEG's use lossy compression to manage file size.
ò each time you save a JPEG, you lose some data and reduce image quality.

.TIFF (.TIF)
ò stands for Tagged Image File Format
ò TIFF's are good for the exchange of images between programs and platforms
ò 1 bit colour to 24 bit colour
ò TIFF's are generally uncompressed or they use lossless compression

.PNG
ò pronouced PING
ò stands for Portable Network Graphics
ò PNG is a very flexible format
ò These files can be palette-based, grayscale, or true color images with color resolutions of up to 48 bits.
ò PNG uses cross-platform color and gamma correction
ò indexed PNG's are almost always smaller than identical GIF files.
ò unlike GIF, which only lets you to choose a single color to be transparent, PNG provides full alpha transparency, meaning you can have images with graduated transparency
ò PNG's can carry information to compensate for brightness variations between Macintosh and PC monitors.
ò however - PNG's are not yet fully supported by the major browsers. Only Netscape 4+ and MSIE 4+ browsers support PNG's, and there are limitations. Gamma correction and alpha transparency are not consistently implemented.

.PSD
ò stands for Photoshop Shop Document
ò these files are only used to save multiple, maneuverable layers. They can be used to save Merged or Flattened Images but the file is not compressed

Compression Types
ò There are 2 different types of compression: LOSSY compression, and LOSSLESS compression

LOSSY Compression:
ò reduces file size by removing "unnecessary" data. The data is eliminated based on a number of sophisticated mathematically-based formulae. JPEG's are the only type of file that uses LOSSY compression

LOSSLESS Compression:
ò is a type of compression algorithm that reduces file size without losing any data. Typically this is done by finding and eliminating redundant information. .BMP, .GIF, .TIFF, .PNG use LOSSLESS compression


NATE

[img http://www.mainframe-webdesign.com/tt/mainframe.gif]
http://www.mainframe-webdesign.com