Hi Joshua, not answering your actual question BUT I would instruct the editors to not update (overwrite) existing images - why? Because it is not just an issue with the "environment" cache but also used CDN (unless you have automatic cache invalidation) BUT also issue with browsers and any public proxy, they might have already cached the image and it will not automatically update for them. So better instruct the editors to not re-use an existing image but upload a new edited version with a new name - less problems with public caching, browser caching etc. Just my 2 cents ;)

I am going to agree with Antti on this one.  I have run into several issues with clients updating files and expecting the updated to file to be reflected asap. Best bet is to have them break the caching by providing a new name for the file.

Thanks with your responses.  I completely agree with all of this.  I have advised them before about this matter as well. I always use the analogy that think of it as a social security number assigned to the image.  That should never change throughout the life of the image.  This is the use case.  They name the image ie(119.png) after the identity in their PIM system.  That image is then referenced to a content item in episerver with 119 in a property of the block.  This block then pulls the 119 from their blob provider.  if it exists, it uses it, else it fetches from PIM and then associates it to the block.  Unfortunately, i don't have control over the image after that as it is saved in episerver and now becomes an ImageFile associated with that block.  Thats really the only usecase but again, i agree with both of you but unfortunately, its out of my hands and all i can do is educate the client.  Thank you both again.