Question

I’m serving images two different ways:

1. Using a PHP script for profile pictures for example
2. By pointing to them directly, for icons and backgrounds for example

I’m in the process of handling their caching properly, and i’m totally new to this.

For the PHP script, i’m just adding a Last-Modified header to the response, and delivering a 304 status code if it’s called again, if the file hasn’t changed (using filemtime()).

For direct accesses, i’m using HTACCESS, but every rule i saw so far doesn’t allow me to do the same as in my PHP script (checking if the file has changed, then serving a 304 or the file itself).

Here’s the HTACCESS rule i’m planning to use:

Header unset Pragma
FileETag None
Header unset ETag

# cache images/pdf docs for 10 days
<FilesMatch "\.(ico|pdf|jpg|jpeg|png|gif)$">
  Header set Cache-Control "max-age=864000, public, must-revalidate"
  Header unset Last-Modified
</FilesMatch>

From what i understand, the only way of updating a cached image is to rename it. Does someone know a way around it? By checking the image’s last modification date for instance?

Answer 1

As @Gumbo pointed out, “Apache should already do that for static files”.
And that’s true, Apache does that, so that kind of stuff works fine:

<FilesMatch "\.(ico|pdf|jpg|jpeg|png|gif)$">
    Header set Cache-Control "max-age=864000, public, must-revalidate"
</FilesMatch>

ps: Sorry @Gumbo, but i asked you to change your answer so that i can accept it, but you wouldnt do it and i had to close that question eventually, so.