Putting the Right Graphics on the Web
The desire to have the highest quality graphics should be self-explanatory. Do you really want to intentionally have graphics that don't look as good as possible? That can be the case if you save the wrong type of graphic to JPG and it can also be a file much bigger than a better-looking version saved in another format.
Size is very important. Smaller graphics allow the Web page to load faster. How do you feel if you visit a page that loads slowly? Larger files can cost you more. They can increase the bandwidth used by your site which could lead to overages if the bandwidth is too high. Your visitors could also face a financial penalty if they go over their download limits. The potential penalty for overages and the slow performance could keep visitors from returning.
Slow loading pages can also be penalized by Google. Page speed is one of the many factors that Google incorporates into their ranking algorithm. So if you have large images that cause the page to load slowly, it could have a negative effect on your SEO. Use the right format for each graphic and optimize the size before posting and you'll see improvement in more ways than you might have expected!