Register a new image size.

Cropping behavior for the image size is dependent on the value of $crop: 1. If false (default), images will be scaled, not cropped. 2. If an array in the form of array( x_crop_position, y_crop_position ):
*- x_crop_position accepts ‘left’ ‘center’, or ‘right’.
*- y_crop_position accepts ‘top’, ‘center’, or ‘bottom’. Images will be cropped to the specified dimensions within the defined crop area. 3. If true, images will be cropped to the specified dimensions using center positions.

Signature

add_image_size( $name, $width = 0, $height = 0, $crop = false )
name
 (string) Image size identifier.
width
 (int) Image width in pixels.
Default: 0
height
 (int) Image height in pixels.
Default: 0
crop
 (boolean|array) Optional. Whether to crop images to specified height and width or resize. An array can specify positioning of the crop area. Default false.
Default: false

Return

(boolean|array) False, if no image was created. Metadata array on success.

Source

function add_image_size( $name, $width = 0, $height = 0, $crop = false ) {
	global $_wp_additional_image_sizes;

	$_wp_additional_image_sizes[ $name ] = array(
		'width'  => absint( $width ),
		'height' => absint( $height ),
		'crop'   => $crop,
	);
}
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