AWS SDK for PHP, uploading an image returns 500 internal server error

Question

I'm attempting to upload an image with AWS PHP SDK. For some odd reason some images aren't uploading?

$s3 = new Aws\S3\S3Client([
            'region'  => 'us-east-1',
            'version' => 'latest',
            'endpoint' => 'https://example.com',
            'use_path_style_endpoint' => true,
            'credentials' => [
                'key'    => $access_key,
                'secret' => $secret,
            ]
        ]);     


        try {

            $result = $s3->putObject([
                'Bucket' => $bucket,
                'Key'    => $file_name,
                'Body' => fopen($file_location, 'r'),
                'ContentType' => $imageType,
                'ACL'   => 'public-read'    
            ]);

        } catch(Aws\S3\Exception\S3Exception $e) {

            echo $e->getMessage();
        }

I can download an image from dummyimage.com and it will upload to a bucket successfully but when i attempt other images s3 returns a 500 internal server error.

How do i solve? There is nothing in the error logs.