Photos All Seem To Upload Successfully, But Only A Few Show

I'm uploading a batch of images to 4.6.0 which seems to go successfully...and Sytist shows the correct number of uploaded images; however, when I try to view the images (on either the admin or the frontend), only a few of them show images....the rest appear to be broken. 

Possibly related... checked my error_log and notice that I'm getting a lot of errors like this "PHP Fatal error:Uncaught exception 'Aws\S3\Exception\S3Exception' with message 'Error executing "DeleteObject", The authorization header is malformed; the region 'us-east-1' is wrong; expecting 'us-west-2'"

Checked AWS settings and everything is set to us-west-2 , so not sure where 'us-east-1' is coming from?

I should also mention that this box was recently updated to PHP7.2 from a 5x version. 

That PHP version change may have changed some PHP settings. 

See: Issues uploading photos

Tim, thank you. That was correct, the PHP update caused the PHP.ini file to use all of the default values. Adjusting those per the link you provided resolved the issue.