a question about refreshing images in the web browser
I'm not sure if this is the most appropriate place to ask this kind of question - if not please give a pointer.
I have images uploaded on some of those image sharing sites like photobucket.com and have posted direct image links to various forums on the internet so that the viewers see directly the images. In the future I intend to do that using my own server.
The viewers usually revisit the same images on a regular basis - for example, some view the images every day and some every third day or so.
I often alter the images with the latest version since those are artworks in progress by simply replacing the file on the server with a new file keeping same name so that the direct image link in the web forums still work and I don't need to edit each of my messages.
The problem is that the web browsers will not retrieve each time the image from the server but from the hard drive of the user. I know that if the user presses the refresh button the image will be retrieved from the server but my question is what happens if the user doesn't refresh. Will the user ever see the updated image? How the browsers work when dealing with retrieving images?
When I do that, using a Mozilla browser for example, and don't refresh it retrieves the images from my hard drive but eventually sometime later it pulls it from the server. I would like to know how does that work?