The Importance of Optimizing Image Size for the Web
Webmasters often forget about the size of an image on their webpage. Depending on the computer and internet speed, an image may load faster on one browser than another. By keeping in mind image file size, you can make your pages load faster and accessible, and increase page crawl rate. The faster your images load, the less people are likely leave that page. Nobody likes a slow website!
Usually when I resize photos for the web, I do use Adobe Photoshop, and make sure that I save the image as “Save for Web.” This way, you will get the best quality looking image and a reasonable file size too.
There are image optimizers that you can also use that are web based and free. Online Image Optimizer allows you to either enter the URL of the image or upload one from your computer. You can then choose the file type to get the best optimized image size for the web.