Web Design ABC - Image Formats: GIF, JPEG, PNG and More.

Image Formats: GIF, JPEG, PNG and More.

When you want to put graphics on your website, you'll face an unexpected problem: what format should they be in? On their own computers, many people save pictures in Windows' default BMP (bitmap) format, but the files it creates are simply much too large to put on a website - they'd take about a minute for visitors to download and use up all your bandwidth in the process.

When you put pictures on the web, you need to consider the trade-off you want between image quality and speed: the smaller the file, the worse it's going to look. To help you out, here's a comparison.

GIF.

GIF stands for Graphics Interchange Format, and was the first image format used on the web. It was invented by CompuServe in 1987, updated in 1989, and hasn't changed since - and it shows. Images stored in GIF format can only use

a maximum of 256 colours, which makes things like photographs and logos look terrible. GIFs popularity is mainly due to it being first and producing very small files, although it is also notable for being the only image format that allows you to create small animations.

Really, the only things you should use GIFs for now are files that have a limited number of colours, and are technical in nature - diagrams, for example, work well in GIF format. Things like photographs that use many colours will come out looking very strange.

JPEG.

JPEG was designed by the Joint Photographic Experts Group, who gave it its name. It was designed as a format suitable for storing high-quality photographs at low file sizes - file sizes small enough to put on the web. Today, the format is supported in almost all web browsers, and is also the format that you'll get photos in if you take them with a digital camera.

The most important feature of JPEG is both the best and worst thing about it: lossy compression. The word 'lossy' means that data is lost from the picture when it is saved at smaller file sizes. Image-editing programs will generally let you choose how much compression you want, from none (highest quality, large file size) to 100% (very small files, but terrible quality). Unfortunately, JPEGs that have been compressed too much come out looking worse than useless, but many people still use high compression settings out of a misguided desire to have the very smallest files possible. If you've ever seen images on the web that look very 'blocky', you've been a victim of JPEG compression.

If you do use JPEG, then, it's really recommended that you turn compression off altogether, or use a maximum of about 25% - the files are quite small already, without going overboard with the compression.

PNG.

PNG stands for Portable Network Graphics, and is the newest web image format in widespread use. It was designed as a replacement for the outdated GIF format, allowing files to use millions of colours instead of only 256. PNG files have smaller file sizes than GIFs, although they are often larger than JPEGs, since PNG compression is lossless (never loses any image quality).

The most useful feature of PNG is that it supports something known as 'alpha transparency': basically, images with transparent backgrounds that blend in perfectly. The only thing stopping widespread adoption of this feature is that it isn't currently supported by Internet Explorer, but there is a workaround for this problem: search for 'AlphaImageLoader' for more information.

Converting Between Formats.

For most purposes on the web, all the graphics you want to use should either be in JPEG format (for photos) or PNG format (for less complicated graphics). That's a problem if you've got a collection of images in all sorts of other formats.

Luckily, a good image editor should be able to convert from any format to any other very easily. In Paint Shop Pro, for example, you simply open your images and save them again using whatever format you want - you can even run the 'Batch Converter', which will convert a whole folder full of files all at once. If you don't have an image editing program, there are plenty of free image viewers that will do the same job for you.

An Issue of Width the Resolution Problem

Beware the Stock Photographer Picking Your Pictures

JSP Java on Your Server

Content is King

Column Designs with CSS

Web Design
◦ 5 Simple Steps to Accepting Payments.
◦ 5 Ways to Avoid the 1998 Look.
◦ 6 Reasons Why You Need a Website.
◦ 7 Ways to Make Your Web Forms Better.
◦ A Question of Scroll Bars.
◦ Ads Under the Radar: Linking to Affiliates.
◦ AJAX: Should You Believe the Hype?
◦ All About Design: Principles and Elements.
◦ An Introduction to Paint Shop Pro.
◦ An Issue of Width: the Resolution Problem.
◦ Avoiding the Nuts and Bolts: Content Management Software.
◦ Beware the Stock Photographer: Picking Your Pictures.
◦ Building a Budget Website.
◦ Building Online Communities.
◦ Clean Page Structure: Headings and Lists.
◦ ColdFusion: Quicker Scripting, at a Price.
◦ Column Designs with CSS.
◦ Content is King.
◦ CSS and the End of Tables.
◦ Cut to the Chase: How to Make Your Website Load Faster.
◦ Designing for Sales.
◦ Designing for Search Engines.
◦ Dreamweaver: The Professional Touch.
◦ Encryption and Security with SSL.
◦ Finding a Good HTML Editor.
◦ Focus on the User: Task-Oriented Websites.
◦ Fonts are More Important Than You Think.
◦ Free Graphics Alternatives.
◦ FrontPage: Easy Pages.
◦ Hints All the Way.
◦ Hiring Professionals: 5 Things to Look For.
◦ How Databases Work.
◦ How the Web Works.
◦ How to Get Your Website Talked About on Blogs.
◦ How to Install and Configure a Forum.
◦ How to Make Visitors Add You to Their Favorites.
◦ How to Run Ads Without Driving Visitors Crazy.
◦ How to Set Up Your Hosting in 5 Minutes Flat.
◦ IIS and ASP: Microsoft's Server.
◦ Image Formats: GIF, JPEG, PNG and More.
◦ It's a World Wide Web: Going International.
◦ JSP: Java on Your Server.
◦ LAMP: The Most Popular Server System Ever.
◦ Making Friends and Influencing People: the Importance of Links.
◦ Making Searches Simple.
◦ Offering Free Downloads on Your Website.
◦ Opening a Web Shop with E-Commerce Software.
◦ tag - they have one extra tag before it. This is the doctype, and it must be present right at the top of your document for it to be valid HTML. There are only really
◦ Perl: Cryptic Power.
◦ Photoshop: a Graphic Designer's Dream.
◦ Picking a Colour Scheme.
◦ Printing and Sending: the Two Things Users Want to Do.
◦ Putting Multimedia to Good Use.
◦ Python and Ruby: the Newer Alternatives.
◦ Registering a Domain Name.
◦ Registering Your Users by Stealth.
◦ RSS: Really Simple Syndication.
◦ Setting Up a Mailing List.
◦ Setting up a Test Server on Your Own Computer.
◦ Some Places to Go For More Information.
◦ Taking HTML Further. HTML might seem like a simple language for web documents, and to an extent, it is - that's what it was intended to be. If you know what
◦ Taking HTML Further with Javascript. Once you've built your HTML pages, you might need them to do something a little more interactive on the client-side (that
◦ Taking Your Website Mobile.
◦ Text Ads: Unobtrusive Advertising.
◦ The 5 Principles of Effective Navigation.
◦ The Art of the Logo.
◦ The Basics of Web Forms.
◦ The Basics of Web Servers.
◦ The Case Against Flash.
◦ The Confusing World of Web Hosting: Making Your Decision.
◦ The Evils of PDFs.
◦ The Importance of Validation.
◦ The Many Flavours of HTML.
◦ The Smaller, the Better: Avoiding Graphical Overload.
◦ The Top 10 Biggest Web Design Mistakes.
◦ The Web Designer's Toolbox.
◦ The Web is Not Paper.
◦ There's More than One Web Browser.
◦ Time for User Testing.
◦ Titles and Headlines: It's Not a Newspaper.
◦ Tracking Your Visitors.
◦ Understanding Web Jargon.
◦ Uploading Your Website with FTP.
◦ Using Flash Sensibly.
◦ Using Quizzes and Games to Get Traffic.
◦ VBScript: Javascript Made Easy.
◦ Websites and Weblogs: What's the Difference?
◦ What Do You Want Your Website to Do?
◦ What You See Isn't Always What You Get.
◦ Which Database is Right for You?
◦ Why Doing It Yourself is Best.
◦ Why Java Will Drive Your Visitors Away.
◦ Why Word is Bad for the Web.
◦ Why You Should Put Your Content in a Weblog Format.
◦ Why You Should Stick to Design Conventions.
◦ Working With Templates.
◦ Writing for the Web.

GoogleSense

Making Money with Articles

Webhosting

RSS
◦ Reading RSS Feeds with an RSS Aggregator