How to add custom image size in wordpress

Paula

I am working on a theme and want to generate a custom image size for particular block of HTML. But the WordPress generates a thumbnail, medium and large on image uploading. The custom image size that I want is 250x250, i can not adjust the thumbnail (150x150) image over 250x250 image block because of blurry the image.

Jacob

You can use the add_image_size() function with the after_setup_theme action hook to generate a new image size.

function wp768_custom_image_size() {
    add_image_size('my_custom_image_size', 250, 250);
}
add_action('after_setup_theme', 'wp768_custom_image_size');

And you can use the following size in the template similar to like this.

if( has_post_thumbnail() ) {
    the_post_thumbnail( 'my_custom_image_size' ); 
}

James

Take a look to the documentation link to know more about the add_image_size() function.

https://developer.wordpress.org/reference/functions/add_image_size/