The stage_file_proxy integration introduced in 3.1.x carries a bug which can cause a fatal error:
TypeError: base64_encode(): Argument #1 ($string) must be of type string, bool given in base64_encode() (line 133 of modules/contrib/image_sizes/src/ImageSizesService.php).
This can happen when previously called file_get_contents() returns false, and this is provided as base64_encode() arg.
Ensure, $valid_file in the 'stage_file_proxy' Part of ImageSizesService.php is really 'valid', eg. with first fetching via stage_file_proxy service and then checking file_exists() and then set $valid_file
Active
4.0
Code
Can you please review this with the current RC5 version - I tested this with stage_file_proxy and it seems that the original issue is not happening anymore. It's actually failing right now and removing the stage_file_proxy check did already solve the problem for me @drupatz