Uploaded pictures, not showing in file manager

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A client mentioned this to me earlier today.
He tried uploading a (large) picture to the filemanager which it did without issue. However the picture was then not visible in the file manager.

It didn't give any kind of error, but after resizing the pic. it worked fine. I'm guessing the file was simply too big, but there was no "File too big" error message.

Anyone know what might be the cause?