Graphics for the web: GIF Format

Written by Richard Lowe

The GIF (Graphics Interchange Format) format was invented in 1987 by Compuserve to allow images to be displayed. This format allows for 256 colors (which was a lot atrepparttar time), compression, interlacing and animation. It is a very powerful format, suitable for many different types of images.

Due torepparttar 134676 limited number of colors, GIF is primarily useful in images with a distinct separation of colors. A cartoon, for example, is ideal forrepparttar 134677 GIF format.

When you save an image in GIF format, you haverepparttar 134678 option to specify how many colors will be saved. By doing this you can decreaserepparttar 134679 size of an image even further. All ofrepparttar 134680 tools which are available to optimize GIF images work by reducingrepparttar 134681 number of colors torepparttar 134682 bare minimum. This can produce astounding results inrepparttar 134683 size ofrepparttar 134684 finished file.

Unlike JPEG, GIF uses a non-lossy compression algorithm. This means that images do not loose bits when they are decompressed. In order to accomplish this, GIF uses a proprietary encoding/decoding scheme called LZW (Lempel Zev Welch). LZW is an excellent compression algorithm which typically results in very small files (in comparison to fully expanded BMP files).

This compression method is actuallyrepparttar 134685 cause of a bit of controversy. As it turns out, LZW is owned by UniSys, and overrepparttar 134686 past few years they have made some attempts to collect licensing fees for products which save inrepparttar 134687 GIF format. These attempts have had mixed results, and has causedrepparttar 134688 development of a new non-proprietary standard called PNG.


Written by Tim North

It's not enough to know *how* to create a web site, you also need to know what makes a *good* web site. Think back on some ofrepparttar web sites you've visited recently. Were you impressed by all of them? Probably not. Many web sites are technically fine, but fail on aesthetic grounds.

The guidelines below will help you to create web sites that are user-friendly and will be well received.

1. Content, content, content! The single most important element in any successful web site is good content. You must have content that is:

* interesting;

* informative; and

* regularly updated.

Without this, it will be difficult to convince people to visit your site again and again. Lots of flashy colours and animated images may look funrepparttar 134675 first time, but it's not enough to keep people coming back to your site. Only good content can do that.

2. Don't overuse character styles such as bold face and italics as this can make your site seem amateurish. Also, underlining should be avoided at all costs as visitors will mistake underlined text for a clickable link.

Similarly, don't wildly varyrepparttar 134676 size of your type unless you have good reason.

3. Don't abuse your colours. Too many colours, or overly garish colours, are one ofrepparttar 134677 easiest ways to spot amateur web sites. Also make sure that you choose a readable colour scheme. White text on a black background may look cool, but it's tough to read, particularly with small text.

4. Leave lots of blank space. Text on computer screens is hard to read atrepparttar 134678 best of times, so don't cram in your text. Start lots of new paragraphs, and leave plenty of space between objects. Headings or horizontal rules are a good way to do this.

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