IMG BBCode/getimagesize only works with relative url if file is on local server

Hi,

 

phpBB 3.2.7

No other style than prosilver

No other language than British English

No extension

php 7.1.26 / MySQL 5.6.42

Firefox 67.0.1

 

When I want to use the IMG BBCode, if the file is on the same hosting space as phpBB and I use full URLs like...

https://www.mywebsite.com/medias/image_file.png

...I get the error message "It was not possible to determine the dimensions of the image. Please verify that the URL you entered is correct.".

It only works is I use relative URLs like...

./medias/image_file.png

 

But...

1/ I can confirm the URL is correct.

2/ Every image file format triggers the same error: png, jpg, etc.

 

My image setting in the ACP:

• Maximum image width per post: 0

 

Thanks!