[kh99]

Actually, it does work for thumbnails, but the added line has to go in a different place than I thought. I added it near the beginning. Here's my code fragment, from includes/class_image.php, around line 760 (I added the line in red):

		if ($thumbnail)
		{
			// Only specify scene 1 if this is a PSD or a PDF -- allows animated gifs to be resized..
			$execute .= (in_array($imageinfo[2], array('PDF', 'PSD'))) ? " \"{$filename}\"[0] " : " \"$filename\"";
		}
		else
		{
			$execute .= " \"$filename\"";
		}
        $execute .= ' -auto-orient ';

		if ($imageinfo['scenes'] > 1 AND version_compare($this->version, '6.2.6', '>='))
		{
			$execute .= ' -coalesce ';
		}

So, that's at least a small improvement since the thumbnails will look right.

Oh, I added that line to the code then went to the admincp, Maintenance > General Update Tools > Rebuild Attachment Thumbnails. But that will probably take a long time (it took me a minute and I only have a few test attachments), so you'd probably want to try it first by attaching a new image, or maybe don't run the rebuild but just let it work for new images, if you've been fixing the existing ones.