How to Optimize Images To Make WordPress Faster, without loosing image quality.
While there are many ways you can do this, the best I came across is WP Smush.it Plugin.
Why Install WP Smush.it plugin?
Images speaks more than hundred words, right?
They make your content more engaging and interactive. But unfortunately, many bloggers forget that the size of an image can dramatically make your blog load slow.
If your blog takes more than 5 sec to load than you are at high risk to increase bounce rate of your blog. Which is absolutely not good for your blog.
How To Install WP Smush.it Plugin?
Installing this plugin on your WordPress blog is very easy.
Simply upload the plugin to your /wp-content/plugins/ directory manually or use the Add New Plugin option in WordPress dashboard and activate it through the plugin menu.
And You’re Done!
How To Optimize Images with WP Smush.it?
After you have successfully installed and activated the plugin, you don’t need to do anything else.The next time you upload an image in your media library the plugin will automatically optimize it on the fly, without loosing quality of the image.
Now you must be thinking, how to optimize your previously uploaded images.
Don’t worry! You can do this through Media Library in WordPress dashboard. See the image below to get a clear idea.
Bulk Image Optimization
Manually optimizing every single image through Media Library can be time consuming, especially, if you have hundreds of images uploaded ( if not thousands).
This where the bulk image optimization can help you save your precious time. Simply go to Media > Bulk Smush.it and click the button which says "Run all my images through WP Smush.it right now".
Now here keep that in mind that it can take some time to processes all images if they have never been Smushed before.
Source : http://www.wp.allhitweb.com/optimize-images-to-make-wordpress-faster