title: How many random elements before MD5 produces collisions?
body: <p>I've got an image library on Amazon S3. For each image, I md5 the source URL on my server plus a timestamp to get a unique filename. Since S3 can't have subdirectories, I need to store all of these images in a single flat folder.</p>
  
  <p>Do I need to worry about collisions in the MD5 hash value that gets produced?</p>
  
  <p>Bonus: How many files could I have before I'd start seeing collisions in the hash value that MD5 produces?</p>