Computer Graphics and Image File Formats (4)

Image File Format <br> How to store an image in an ideal file format is very important. Therefore it is necessary to discuss the best stored file format types for different images. We briefly introduce several image file formats.

AI, Adobe Illustrator
Name: Adobe Illustrator
Extensions: AI
Type: meta format
Standard: Adobe
Platform: Windows and Mac


BMP, Bitmap
Name: Microsoft Windows Bitmap
Extensions: BMP
Type: Raster format
Color: 1 to 32-bit
Version: 1, 2, 3 and 4 (Windows 95)
Compression: RLE or uncompressed
Standard: Microsoft
Platform: DOS and Windows

General view

There are four different versions of BMP. They are often used depending on the number of versions. Different versions usually do not cause problems. File compression uses RLE, which is a non-destructive compression method. BMP files can be stored Colors. Screen shots rarely need to be saved as extra 8-bit colors (256 colors). Photos should be saved as 24-bit colors.

advantage

Most Microsoft software can easily import and export BMP files.

Shortcomings

The file size is usually large because 24-bit images are often stored without compression.


CGM
Name: Computer Graphics metafile
Extensions: CGM
Type: meta format
Color: Unlimited
Version: 1, 2, 3 and 4
Template: CALS, ATA, J2008 etc
Compression: Different for each version
Standard: ISO (IEC 8632)
Platform: DOS, Windows, Macintosh and UNIX

Benefits The latest version has become so complete that it can be used as a storage format. Unfortunately, there are very few images and word processing software supporting version 4. CGM is an ISO and MIL standard. This makes this format widely used in certain industries.

Disadvantages The common problem is that almost no image and word processing software can input and output this format very well.


GIF

Name: Graphics Interchange Format
Extensions: GIF
Type: Raster format
Compression: LZW
Color: 1 to 8 bit-color (Max 256 colors)
Version: GIF87a and GIF89a
Standard: CompuServe Incorporated
Platform: DOS, Windows, Macintosh and UNIX
Advantages Most image software can input and output GIF files.

This file format provides very small files, which can provide fast download and display speed on the web.

Disadvantages The fact that only 256 colors are stored in the guide file means that it is difficult for you to use it as a photo without wanting to lose a lot of quality.


JPG

Name: Joint Photographics Experts Group File Interchange Format
Extensions: JFIF, JFI, JPG, JIF and JFIF
Type: Raster format
Color: 1 to 24-bit
Standard: ISO (IEC 10918)
Platform: DOS, Windows, Macintosh and UNIX
The advantage of this format is that it provides good compression, especially for photos. This compression will reduce the file size by about 5 to 20 times.

Since this format is widely applied to the Internet, you will find support for this format in most software.

ISO-standard

Disadvantages This format applies damage compression. This means that you will lose some information when you save your image. You should not use JPG as an original copy for your image.


PCD

Name: Photo CD
Extensions: PCD
Type: meta format
Color: 24-bit
Standard: Kodak
Platform: Mac