With the same code on two different web server I found two different results ! I use PHP7.3 fpm on both.
The file path is something like
"http://fitantanana/viewimage.php?modulepart=medias&entity=1&file=image/test_Exemple_doc.png"
On the server returning an error, the PHP error log contains
"PHP Warning: imagecreatefrompng(http://fitantanana/viewimage.php?modulepart=medias&entity=1&file=image/test_Exemple_doc.png): failed to open stream: php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution in ..."
As you can see, the requested URL has been change : all the characters & have become &.
Thanks in advance for your ideas.
Best regards, Sylvain Legrand.