brunomonteiro3

This plugin hasn’t been updated in years. I think the creator abandoned it.

Anyway, I recommend you to check the folder permissions “wp-content/uploads” and “wp-content/plugins/wp-post-thumbnail/cache”. Set them to 777 and probably your problem will be solved. ??

Hey guys! I had the same issue but using WP Post Thumbnail plugin. Since it is quite old (almost three years without updates), it was obvious that a WordPress update will result in some errors. Well, even being a old plugin, it is VERY useful for me, so I had to fix asap.

I opened the archive and found the line that the error was. It was a query that was getting all the uploaded images on the post. The query was like this:

function getPreset() {
	global $wpdb;
	return $wpdb->get_results( $wpdb->prepare( "SELECT * FROM $this->wppt_preset_db" ) );
}

Since the WordPress update changed a few things of how $wpdb->prepare() works, all I need to do is add:

$query = (string) $query;

Before this query. The result will be like this:

function getPreset() {
	global $wpdb;
	$query = (string) $query;
	return $wpdb->get_results( $wpdb->prepare( "SELECT * FROM $this->wppt_preset_db", $query ) );
}

Note that this solution is for WP Post Thumbnail plugin, but I posted the solution that worked for me here for maybe help someone with this same issue or something similar.

Cheers!

Sorry, duplicated replies. Please delete this post.