If you have ever sent or received photos via email, or attached them somewhere on the web, you know that image size can be a problem. Some websites only allow small images so they load faster and consume less memory, and getting an email with a huge image can be very annoying.
This is why we "resize" our images. The aim of optimization is to reduce the time it takes to access a website (or run a program).
The time it takes for a webpage to display is affected by a number of factors:
- number (and filesize) of images used on the webpage
- structure of the underlying XHTML code, for example; setting height and width attributes enables the browser to reserve the correct amount of space for an image (before it has downloaded) avoiding the browser redrawing the webpage
- browser’s rendering engine (how the program is used to access the web loads on each webpage)
- browser caching: if the webpage, images, stylesheets, etc. are stored locally they do not need to be downloaded
- user’s connection speed (i.e. dial-up modem will take longer to download a webpage than a cable modem)
- speed of the server hosting the website
- Internet traffic