Outputting multiple images

I've found a little problem that's not explicitly a php problem but I was hoping that php may be the solution. Someone is shown an image and then asked if they wish to change that image. If they answer yes they are taken to an upload form and the new image is upload to the server overwitting the old image using the same filename. They are then taken to a page to show them the image they just uploaded but the old image is diplayed from cache instead of the new photo being shown. I'm using absolute path to the image on the server, not URL. Is there a way to get the script to load in the new photos? Ed