Missing feature image link function

Question

I need to be able to add a feature image to a post as a link. The link is good, it's green check. And no I cannot upload the file and insert into post. I have the link to the image I just want feature image to use it. Why I dont want to upload it, it's because my gallery is completely OUTSIDE awful WP gallery system ! and work great as this

SO the question is. If my link is : http://www.notreaventure.com/photo-0007/images/_MG_2133.jpg and I want WP to use it as feature image, can I put this link in a custom files, let's say featureimg : http://www.notreaventure.com/photo-0007/images/_MG_2133.jpg, and add a funtion that tells the WP system to get this field and get it to feature image, so nothing will be broken. I just cannot seem to find how to hack wp to get the funtion feature image to get it's image from custom field...

can you help, thanks in advance

Answer 1

Yes, you've guessed it right. You will need to use Custom Fields in order to define the URL for the Image that you wish to use as Featured Image for the post.

Next part is to tell the Wordpress to use the Image from URL you've in Custom Field as Featured Image. Here, you can use filter called "post_thumbnail_html". The Filter is defined in "wp-includes/post-thumbnail-template.php" file under function "get_the_post_thumbnail" and also available in the latest version of Wordpress.

The definition goes like this:

return apply_filters( 'post_thumbnail_html', $html, $post_id, $post_thumbnail_id, $size, $attr );

Here is a sample use of it:

function custom_post_thumbnail($html)
{ 
    return "<img src='https://www.google.co.in/images/srpr/logo3w.png' />";
}
add_filter('post_thumbnail_html', 'custom_post_thumbnail');

Note that above code snippet is just to give you an idea of how to use this filter. You will need to add required code to get the Custom Field value and return proper IMG tag. The best thing I would suggest to do is merely parse the Image SRC part of $html and replace it with your URL. Also don't forget to check if the Custom Field is empty; in that case, just return the default $html without altering.

I hope this helps.

Cheers,

Ruturaaj.