Use Exact Image Size using add_image_size

Question

I have a pretty basic question. It may be very noob question, but it is bothering me a lot. In my theme I've added a custom image size like this:

function img_update() {
    if ( function_exists( 'add_image_size' ) ) {
        add_image_size( 'blog_feat_img', 720 );
        add_image_size( 'latest_posts_widget_feat_img', 400 );
        add_image_size( 'portfolio_widget_feat_img_1x', 400 );
        add_image_size( 'portfolio_widget_feat_img_2x', 800 );
        add_image_size( 'blog_body_img', 740 );
    }
}
add_action( 'after_setup_theme', 'img_update', 11 );

Now I used another function to add that in media dropdown list, like this:

function mytheme_image_size_names( $sizes ) {
    $sizes['blog_body_img'] = __( 'Blog Body Image', 'isaumya' );

    return $sizes;
}
add_filter( 'image_size_names_choose', 'mytheme_image_size_names', 11, 1 );

Everything fine but I'm having a wired issue. When Iupload an image of 1024x768 it should generate a 740x555 copy as I didn't mention the height, so it should take the proper height as per that width. But instead it is generating 650x488 version for blog_body_img. I have no idea why. I've also tried to pass 0 as height and then true as the crop parameter. Still it generates 650x488 version and not 740x555. Why?

Can anyone help me out with this?

Answer 1

At last I've fixed the issue. In my parent theme, the dev have used the following code

if ( ! isset( $content_width ) )
{
    $content_width = 650;
}

which means if the value of $content_width has not set up yet then set it to 650. Now in my chield theme at the time of overwriting and mentioning image type I've just added few more lines like this:

function img_update() {
    global $content_width;

    if ( isset( $content_width ) )
    {
        $content_width = 740;
    }

    if ( function_exists( 'add_image_size' ) ) {
        add_image_size( 'blog_feat_img', 720 );
        add_image_size( 'latest_posts_widget_feat_img', 400 );
        add_image_size( 'portfolio_widget_feat_img_1x', 400 );
        add_image_size( 'portfolio_widget_feat_img_2x', 800 );
        add_image_size( 'blog_body_img', 740 );
    }
}
add_action( 'after_setup_theme', 'img_update', 11 );

This type I have checked if the value of $content_width has already been set. Which is virtuosos because my function in priority 11 so the parent theme func with first set the value then I overwrite it.

Every thing is fine now.

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Answer 2

Use '9999' as a height limit for the add_image_size function. Thus, you will have your ratio saved without cropping or squishing the image and only width limit will be followed.

Height is required and has no default value (see here: https://developer.wordpress.org/reference/functions/add_image_size/)