PHPデバッグをONにしてから、再度、サムネイルの再構築をやってみると
サムネイル再構築の画面メッセージは、

Warning [PHP]: imagejpeg(): Unable to access /****/****/xoops/uploads/thumbs/1.jpg
in file modules/myalbum/include/functions.php line 149
Warning [PHP]: imagejpeg(): Invalid filename '/****/****/xoops/uploads/thumbs/1.jpg'
in file modules/myalbum/include/functions.php line 149
Warning [PHP]: imagejpeg(): Unable to access /****/****/xoops/uploads/thumbs/2.jpg
in file modules/myalbum/include/functions.php line 149
Warning [PHP]: imagejpeg(): Invalid filename '/****/****/xoops/uploads/thumbs/2.jpg'
in file modules/myalbum/include/functions.php line 149

と表示され、ホームページの上部には

Warning: getimagesize(): Unable to access /****/****/xoops/uploads/thumbs/2.jpg
in /****/****/xoops/modules/myalbum/blocks/myalbum_topnews.php on line 59

Warning: getimagesize(/****/****/xoops/uploads/thumbs/2.jpg): failed to open
stream: No such file or directory in /****/****/xoops/modules/myalbum/blocks/myalbum_topnews.php on line 59

Warning: getimagesize(): Unable to access /****/****/xoops/uploads/thumbs/1.jpg
in /****/****/xoops/modules/myalbum/blocks/myalbum_topnews.php on line 59

Warning: getimagesize(/public/****/****/xoops/uploads/thumbs/1.jpg): failed to open
stream: No such file or directory in /****/****/xoops/modules/myalbum/blocks/myalbum_topnews.php on line 59

と表示されます。
このメッセージは何が原因でしょうか？