When using Public-Accessible S3 buckets, how are there not collisions with other Public-Accessible S3 bucket and object names?

I have an S3 bucket my-bucket and an object in that bucket my-image.jpg

In order to display these images in a website, directly out of S3, I've put this bucket policy on my-bucket:

{
    "Version": "2008-10-17",
    "Statement": [
        {
            "Sid": "AllowPublicRead",
            "Effect": "Allow",
            "Principal": {
                "AWS": "*"
            },
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::my-bucket/*"
        }
    ]
}

Now, in my website, I can conveniently just do this in my HTML:

<img width="400" height="400" 
            src="http://ift.tt/1H53JiI">

But what is stopping someone, somewhere, from making their own public my-bucket, and adding a my-image.jpg? How will it load the proper image? Does S3 handle this in some way?

note No, these are not the actual bucket names + image names. They are examples.