1. Avoid images that only have text. Use a paragraph tag because it will be easier to edit the text and because it cuts down on the loading time.
2. Use thumbnails if there are a lot of images on your web page. Hyperlinks can be added to thumbnails which open up the original image.
3. JPEG is ideal for complex images and photographs. Use this for realistic photos. These images do not support transparency.
4. GIF is used for images that have 256 colors or fewer. They support transparency. They are mostly used for logos or icons.
5. PNG use lot more colors than GIFs and support better quality transparency. Use these images when text is prominently featured.
6. Raster images are pictures that are made up of pixels.