Optimization is reducing the file size of an image is to a minimum without changing the look of the graphic. The reason you optimize Web graphics is that smaller file sizes result in faster page loading. That way, site visitors don't have to wait too long for your material to appear. Recommended load time for a page is 30 seconds maximum.
The file size of a GIF or JPG image depends on:
The dimensions (width and height). · The number of colors. · The complexity (number of pixels).
Reducing the number of colors (GIF) will slim down the file size. Reducing the quality (JPG) also produces a smaller file.
Image editing programs come with a Crop tool to remove extraneous portions of an image. Use it freely. PhotoShop also has tools to give you a curved frame, shadows, blurred edges and other effects.
Grayscale images contain 256 shades of gray (white and black included). If you save a black and white image as grayscale., you'll reduce the file save and save some bytes.
Keep the actual dimensions as small as possible without losing visibility. If you want site visitors to be able to look at full-screen images, turn them into thumbnails that expand to full size when clicked.
