wordpress - Any Ideas Why this PHP If / Else Function Doesn't Work? -

i've written 2 functions work on wordpress site , having trouble second one. first function scans post image. if finds one, selects main image of site. if there's no image, defers default image. here's function:

function main_image() {     global $post, $posts;     $first_img = '';     ob_start();     ob_end_clean();     $output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $post->post_content, $matches); $first_img = $matches [1] [0];     if(empty($first_img)){         //defines default image         $first_img = "http://www.example.com/image.jpg";     }     return $first_img; } 

the code above works fine. second part, i'm trying specify if default image used, twitter card should set "summary." if image found, twitter card should set "summary_large_image."

here's function:

function twitter_card() {     global $post, $posts;     if ($first_img = "http://www.example.com/image.jpg") {         echo "summary";     } else {         echo "summary_large_image";     } } 

the second function isn't working correctly, returns "summary," whether listed image used in post or not.

if know why second function doesn't work, i'd love insight.

thanks!

you need == not =.

== comparison
= assignment

as $first_image, make variable outside function , in function write:

try this:

function twitter_card() {      global $post, $posts;      if (main_image() == "http://www.example.com/image.jpg") {          echo "summary";      } else {          echo "summary_large_image";      }   }