I'm setting up a Drupal 8 website and I can't seem to upload images beyond 3.5mb on my production server. My local development environment has no issue with uploading images to the 16mb limit I set in php.ini.
Since I'm working in Drupal, which is of course PHP, you might assume the limitation is coming from the PHP settings. However, in my php.ini I have upload_max_filesize = 16M, post_max_size = 18M and max_execution_time = 300. I'm able to confirm this in a phpinfo() print out.
Also I can upload files below 3.5mb just fine so I don't believe it's permissions either.
I'm pretty sure it's not Drupal, PHP nor permissions getting in the way. Does anyone have any idea as to what might be another area to look? I'm running Centos7 with of course Apache2.