Create an instance of add_image_size
When you upload an image, it’s saved, and a copy is created for every image size, resized to the appropriate dimensions. When you specify a set of dimensions manually, e.g. wp_get_attachment_image_src($id, array(57, 57)) the 57×57 dimensions are compared to the image sizes, and the nearest image size is chosen and that image is returned. So … Read more