AFAmazonS3Manager acceptable content-types for images

I'm using AFAmazonS3Manager in order to manage images. I've uploaded a test image named test.jpg into my bucket. However, when executing the below code, I get a code -1016 failure for unacceptable content-types. How do I add image/jpeg as an acceptable content-type?

s3Manager.requestSerializer.region = AFAmazonS3USWest1Region;
s3Manager.requestSerializer.bucket = @"BUCKET_NAME";

[s3Manager getObjectWithPath:@"/test.jpg" progress:^(NSUInteger bytesRead, long long totalBytesRead, long long totalBytesExpectedToRead) {
    NSLog(@"%u", bytesRead);
} success:^(id responseObject, NSData *responseData) {
    NSLog(@"%@", responseObject);
} failure:^(NSError *error) {
    NSLog(@"%@", error);
}];