Image Format Options

• GIFs (Graphics Interchange Format), PNGs (Portable Network Graphics) and JPGs (Joint Photographic Experts Group) are the primary image formats used on web pages. Although all images can be saved as any type of these three files, each image is generally best suited for one of the types.
  
  Also, when selecting what type of format you're image will be, remember to keep in mind the image's quality and file size. These two factors affect the way an image will look and how fast it will load, regardless of the image format.
  
  

GIFs and PNGs

• Images like logos, buttons, cartoons and other graphic text--meaning low- and flat-color images--are best saved as GIFs and PNGs. GIFs and PNGs are also better for anything that will be animated, such as banner ads.
  
  For images with small dimensions, such as 100 x 100 pixels or less, GIFs and PNGs generally create smaller file sizes with the same or better quality as the corresponding JPG. This can even hold true with small smooth-toned images, such as photographs, which are generally better off in JPG format.
  
  

JPGs

• Unlike GIFs and PNGs, which display a maximum of 256 colors, JPGs are capable of displaying millions of colors at once, which is why smooth-toned images, such as photographs and artwork, should be saved in JPG format for use on web sites. JPGs are meant to compress realistic images, color and black and white, and maintain the hues and other true-color elements of photographs. However, hard-edged photographs with areas of very flat color are better suited to GIFs or PNG format, whereas large photographs are ideal for JPG format.
  
  Whether GIF, JPG or PNG, choosing the right image format when saving your files for the web can make a big difference when it comes to the appearance and speed of your website, meaning the overall optimization. So take the time to experiment and get the images looking as good as possible in as small of a file size as possible before loading them to your web site.