After update to php 7.4 the "Notices" as followed are generated during image generation process:
Notice: Trying to access array offset on value of type bool in /var/www/html/public/phpThumb/phpthumb.class.php on line 237
Notice: Trying to access array offset on value of type bool in /var/www/html/public/phpThumb/phpthumb.class.php on line 239
After update to php 7.4 the "Notices" as followed are generated during image generation process: