Width and Height IMG Attributes
The HTML <img> tag element specifies the box size to the website browser to embrace the graphic and hence the browser can continue loading the rest of the web page as the image is being downloaded. In absence of width and height attributes the web browser stops downloading till the image is downloaded.
What Number of Images to use?
Large number of images on the web page slows the downloading speed, since photos constitute more than the fifty percent of download time of the web page. Use the right numbers of images (few) so that the downloading time is not hampered and the user is happy.
Photos should be clear, optimum in color and resolution. Use a graphic editor to remove noise and other unwanted features. Most editors will correct red-eye and sharpen the edge. Some photo editors let you change the background, adjust color level.
Always convert graphic text into stylized text and keep images to the required size on the web page. Graphic help enhance the website usability and help in information to the user that which he or she is seeking. Unnecessary usage of images is not good.