The graphics on my Web pages are all now in GIF format. Someone told me that I should convert all these GIFs over to JPEG format, because it is faster and better. Is this true?
Not necessarily. It depends on the kind of image.
The JPEG graphics format is certainly a more “high-tech”format, in that the mathematical algorithm used for imagecompression is more complicated and harder to implement, which is why the early versions of Web browsers only supported inlineGIFs. In those early days, you could only view JPEG imagesvia an external viewer or helper app.
Now every browser supports inline JPEGs, leading some peopleto think you should convert all your graphics to this more advanced format. However, different compression algorithmsbehave differently depending on the image data. Thereare many situations in which GIF is the better format.
GIFs are good for computer-generated graphics, for examplethose generated by drawing programs like Adobe Illustratoror MacDraw. Typically, these graphics have large flat orevenly shaded areas, with not a lot of detail or surfacetexture. Because the GIF algorithm looks for repeatingsequences of pixels, it will compress these kinds ofimages very well.
JPEG on the other hand, was designed by the Joint PhotographicExperts Group, and is suited more to photographic or natural-lookingimages rather than computer illustrations. These photographicimages tend to have a lot of texture and irregular shapes.Because the compression algorithm does not depend onrepeating sequences of pixels, it works better for thesekinds of images than GIF compression.