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quick tips

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quick tips

bitmapped (or rasterised) graphics

When producing new versions of a graphic from the original, always use the original to make each new version. This will retain as much of the quality as possible. And always ensure that the image mode is on rgb color.

This is because each time a graphics package shrinks an image, it reduces the number of colours, therefore reducing the quality. So if you use the original every time, you will always get the most colours possible.

This also means that unless the image is a vector image, you can't create a good quality larger version as there won't be enough colours to render the image at the same quality.

Once a graphics package, such as Adobe Photoshop or Macromedia Fireworks, has optimized the graphic, you cannot get back to the original quality. Gifs are indexed color and jpgs may have have their quality reduced to shrink the file size.

There will always be the sacrifice between quality and file size - smaller file size = quicker download times.

re-sizing images in a web page

Never use the width and height attributes of the <img> tag in the html of a web page to resize images. If you use this method to reduce the image size, you will increase the download time of the page as a whole. This is because the browser has to "re-draw" the image at an incorrect size which takes longer.

In addition, never use this technique to increase the size of an image - it severely reduces image quality as well as taking longer to download. Use you favorite graphics software to re-size your images properly and include the correct width and height dimensions for a speedier download. This means your site will look better, and your visitors will be happy with a quicker download time.