Each object in Amazon S3 has a set of key-value pairs that represents its metadata. There are two types of metadata:
System metadata – Sometimes processed by Amazon S3,
User metadata – Never processed by Amazon S3.
User metadata is stored with the object and returned with it.
The maximum size for user metadata is 2 KB, and both the keys and their values must conform to US-ASCII standards.
This section explains how to use the console to add and remove the metadata associated with an object.
To edit the metadata of an object
Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.
Click the object whose metadata you want to edit, and then click Metadata.
Do one of the following:
User-defined metadata names must begin with "x-amz-meta-", otherwise Amazon S3 will not set the key value pair as you define it.