选项树输出未显示在主题选项中？

I am using option tree in my WordPress theme. I am trying to set a theme option for uploading an image for changing the logo image. All is set but I am using this code to show the output, but it doesn't work. How can I solve this ?

<?php
    if ( function_exists( 'ot_get_option' ) ) {
        $images = explode( ',', get_post_meta( get_the_ID(), 'logo_image_url', true ) );
            if ( !empty( $images ) ) {
            foreach( $images as $id ) {
                if ( !empty( $id ) ) {
                    $thumb_img_src = wp_get_attachment_image_src( $id, 'logo-small' );
                    echo '<img src="'. $thumb_img_src[0].'" alt="" />';
                } //ENDIF EMPTY ID
            } //ENDFOREACH
        } //ENDIF EMPTY IMAGES
    } //ENDIF FUNCTION EXISTS
?>

The issue might be the if statement checking for the function ot_get_option. You aren't declaring or using that function so there isn't a need to check if it exists.

You might also check that logo-small is a valid image size registered with add_image_size.