Images

"The construction of images for the web is a little outside of the remit of this website, but it is worth noting a few things...

The most commonly used file formats used for images are GIFs and JPEGs. They are both compressed formats, and have very different uses.

GIFs can have no more than 256 colours, but they maintain the colours of the original image. The lower the number of colours you have in the image, the lower the file size will be.

GIFS SHOULD BE USED FOR IMAGES WITH SOLID COLOURS.

JPEGs on the other hand use a mathematical algorithm to compress the image and will distort the original slightly. The lower the compression, the higher the file size, but the clearer the image.

JPEGS SHOULD BE USED FOR IMAGES SUCH AS PHOTOGRAPHS.

Images are perhaps the largest files a new web designer will be handling. It is a common mistake to be oblivious to the file size of images, which can be extremely large. Web pages should download as quickly as possible, and if you keep in mind that most people use modems that download at less than 7Kb a second (realistically it is less than 5Kb), you can see how a large file will greatly slow down the download time of a full page.

You need to strike a balance between image quality and image size. Most modern image manipulation programs allow you to compress images and the best way to figure out what is best suited for yourself is trial and error."