If you find that images are not loading in linux server then you should disable PHP functions.
php.ini is configuration file of PHP.
Find exact path of php.ini
# php -i | grep php.ini
Or you can use the another command like
Configuration File (php.ini) Path => /usr/local/lib
Loaded Configuration File => /usr/local/lib/php.ini
then search disabled disable_function in that file and remove “readfile” optionin in that line.
then restart apache service.
All images should be work fine.