Insert image into sub-field with update_post_meta

Question

I found out that I could insert an image into a custom sub-field by just adding the image ID:

update_post_meta($post_id, $metafield, 168);

But that was a lucky guess - I didn't see this info on the documentation for "update_post_meta".

But if I use this way, how do I specify the size of the image? And maybe setting css-classes, such as "alignright"?

Previously I had tried to add the image by writing:

update_post_meta($post_id, $metafield, '<img src="' . $img[0] . '" alt="' . $img_alt . '"/>');

..which required me to get the "src" and specify the size:

$img_id = 233;
$img = wp_get_attachment_image_src( $img_id, 'medium');

and get the "alt" by doing:

$img_alt = get_post_meta($img_id, '_wp_attachment_image_alt', true);

So the first option is simpler, but I wonder how to add more specifications to it?

Answer 1

Yeah, don't do that.

The database is not made to store HTML, HTML and PHP are made for that.

You'll want to just save the image. For example:

update_post_meta($post_id, $name, $img);

$name is the name of the postmeta in the database and $img is the URL of the image.

To later on display the image:

<img src="<?php echo get_post_meta($post_id, $name, true);?>

This will return the image. If you want to store more information about the image (height, width, etc) you will need to store them seperately, or store all the information in 1 array.

Storing in an array:

$content = array(
    'img'=>$imageurl,
    'width' => $width,
    'height' => $height,
    'othertotalyawesomeoption' => $other
);

update_post_meta($post_id, $name, $content);

To output the image:

<?php $data = get_post_meta($post_id, $name, true);?>
<img src="<?php echo $data['img'];?>" height="<?php echo $data['height'];?>" width="<?php echo $data['width'];?>">