title: How to clear browser cache when re-uploading image with same filename, in php?
body: <p>I have a listing of items, that also contains an image thumbnail. Sometimes I need to change the thumbnail image, but keep the filename the same. Is there a way to force the browser to download the newly uploaded image, instead of grabbing one from the browser cache?</p>
  
  <p>This is very pertinent when people update their avatars, which causes confusion for some users, who keep seeing their old avatar, until they clear the browser cache, or restart the browser. </p>