Images often account for most of the downloaded bytes on a web page and also often occupy a significant amount of visual space. As a result, optimizing images can often yield some of the largest byte savings and performance improvements for your website: the fewer bytes the browser has to download, the less competition there is for the client’s bandwidth and the faster the browser can download and render useful content on the screen.

Image optimization is both an art and science: an art because there is no one definitive answer for how best to compress an individual image, and a science because there are many well developed techniques and algorithms that can significantly reduce the size of an image. Finding the optimal settings for your image requires careful analysis along many dimensions: format capabilities, content of encoded data, quality, pixel dimensions, and more.
Various Tools (both Online and Offline and Free and Commercial) are available to optimize your Images on your Website.
If you need help please contact me for a no obligation look at your Images.