Thats what i have been doing not enocunterd any issues as such yet with Nginx or PHP i am also curious if it possible to execute compression of images via Nginx, For those of us who use CloudFlare.com already know that cloudflare performs lossless image compression most likely the same way via linux.
On windows we have the following tool avaliable what just executes a series of command line tools to compress images. http://nikkhokkho.sourceforge.net/static.php?page=FileOptimizer aswell as various other files zip, rar, gzip, png ,jpeg the list is endless.
But to save having to compress images manualy especialy if dealing with a site that takes image/media uploads could we not have nginx execute the program via a command line module for images it is serving.
I looked through the modules list the only one i could find that might make use of the exec function is the following. http://wiki.nginx.org/HttpEchoModule
http://wiki.nginx.org/3rdPartyModules