(Solved) Simple cache question

[eluser]Eric Cope[/eluser]
I contemplated the same question several years ago. I thought about copying the files to a temporary location. The disadvantage is that high volume sites require significant disk accesses, which can reduce performance. Back when I first solved this problem, I used htaccess files. I did not like that solution, but it met my needs.

However, let me ask a question from a different point of view. Why do you want a browser to cache an image when you do not want it shared publicly? A similar case to yours (as far as I can tell) would be a stock photo site like istockphoto.com. They sell images, so they do not want their products publicly available. Their solution is to make low resolution watermarked images (you can do this with a php script) publicly available which are cached by browsers. Then, when customers purchase images, they go to a link which does what you do, serves out a photo above the web root. Would this type of solution work for you?

If you share your application, I may be able to offer more targeted advice...