In this current world to cope up with everybody else. Our wordpress site should be faster than before. To achieve this you need to optimize your images in the site. To optimize the images in the wordpress site you need to use the below plugin.
reSmush.it Image Optimizer https://wordpress.org/plugins/resmushit-image-optimizer/
WP Smush.it: https://wordpress.org/plugins/wp-smushit/
ShortPixel Image Optimizer: https://wordpress.org/plugins/shortpixel-image-optimiser/
You can also use EWWW Image Optimizer, CW Image Optimizer, Tiny Png, Imsanity and Hammy.