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During the course of a normal business day you may be sent images that are in a JPEG, GIF or PNG format. Alternatively you might have to decide which format is best for compressing an image that you need to professionally print.
If you need to create a company brochure, Webpage, or perhaps a Microsoft® PowerPoint presentation, you will probably have to deal with one of the image formats.
So, what is each format, and when should you choose to use one type before another?
JPEG
Named after the Joint Photographic Experts Group that designed it, a JPEG is a digital image file format designed for maximum image compression. It is the best way to format your colourful photos.
Sometimes called a .jiff, .jpg, .JPG, or .JPE, the format has been around for a shorter time than the GIF, but is now the most commonly used method of compressing photographic images on computers. It can display photos and graphics with millions of colours, compresses well and is easy to download.
It uses a “lossy” compression technique which means during the compression process some of the image data is lost. This eliminates redundant or unnecessary information so that the finished image is as small as possible.
GIF
Designed by CompuServe, the GIF is one of the most popular formats on the Internet because it is more widely supported by Web browsers than the JPEG format. It is well suited for compressing areas of images with large areas of the same colour – such as computer-generated art and line drawings. It is also a good option for putting animation online. Images are compressed in to a 256-color or 8 bit image.
The GIF format supports transparency which allows a graphic designer to designate the background colour of an image. For example, if you place a GIF image in a red box the background will be red.
It also supports “interlacing“. This creates the illusion of faster-loading graphics at a Website. It does so by showing the image first in a blurry form, and then gradually defining the image as more information is downloaded from the server.
PNG
The Portable Network Graphic (PNG for short – pronounced Ping) was designed to replace the GIF file format, however because it does not support animation it will never totally supersede the GIF. It is a “lossless” compression format (as are GIFs) which means it is compressed by a technique in which no data is lost. A PNG image is more vibrant with 48 bit true colour, compared to the older GIF's only 8 bit colour.
Other image formats
- The TIFF: Created for simple desktop publishing. A TIFF (Tagged Image File Format) is an old but popular format for colour and black-and-white line images.
- Bitmap or pixmap: The term bitmap comes from the computer programming terminology, meaning just a map of bits. This image format stores the image as a pattern of memory bits, each of which specifies the colour of a pixel of the image.
- EPS: An Encapsulated Postscript is a computer file standard set by Adobe for printers. It is the mathematical definition of shapes, lines, colour and space. This is one of the most accurate ways to define a font or image, but creates a very large file size.
Image resizing
Once you have decided which image format you are using for your in-house marketing materials, internal newsletter, or end-of-year report, you will probably need to resize your image.
This can initially seem like a tricky exercise, however many resources exist to talk you through the process. HP Photosmart Essential 2.5 is free software available at the HP Website which will help you edit, organise, print and share your pictures. Another easy way to share is with Snapfish, the web-based image sharing and print service, while HP Webpages also contain many tips and how-to guides on resizing images. |
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Printable version
