Create Custom Image Sizes For Your WordPress Theme

When uploading into wordpress,it automatically generate other image sizes with uploaded. The default image sizes are setup on the settings -> media screen.     Wordpress by default allow you to use only 3 image size i.e thumbnail,medium,large,If need more images to use you can use following php coding into your functions.php inside theme folder It uses the WordPress function add_image_size to add a new image size to your WordPress theme.

     if ( function_exists( 'add_image_size' ) ) {
	add_image_size( 'custom-image-size1', 300, 9999 ); //300 pixels wide (and unlimited height)
	add_image_size( 'custom-image-size2', 220, 180, true ); //(cropped)
     }

use the function the_post_thumbnail() to use this image on page . Now we can pass this params into the function to display the image because  we have named the image as custom-image-size1.

if ( has_post_thumbnail() ){
    the_post_thumbnail( 'custom-image-size1' );
}