Color contrast between the background and foreground affects the readability of the content.
If the contrast is too small, the text and background can flow into one another and so the text disappears or becomes difficult to read for people with different types of color deficits or people who are using monochrome displays.
Graphics , Images and Multimedia
Images can set the tone of a page. A good image can help to make the page more visually appealing and reinforce the message of your page. Generally web images take up the majority of the download time in most web pages. This can be improved by making the graphics as small as possible.