How I can check all my images on server, they don't prepared with maulicious code ?
I mean for example Gif PHP exploits and so on...
Is this a homework question?
How to harden a server is well beyond the scope of an answer here - as is an introduction to writing secure systems or application level firewalling or systems management. Suffice to say that you should take adequate measures to ensure that it should not be possible to deploy malware on your server. But even if you're an expert systems/network admin and programmer then monitoring the integrity of your system should still figure in your defences.
I assume you mean something like this. As above this kind of attack is only possible if your webserver is configured to allow it and you are dumb enough to allow users to upload unverified content into your document root.
But as I said, even if you've plugged all the security holes, you should still run an integrity checker to check for unauthorized file modifications - go track down a suitable host-based IDS for your operating system (you didn't say what that was) and start monitoring your file signatures and compare them with an offline list.
I used ImageMagick--a image editing software library you can integrate into any exisiting programing language, to convert each image from its type to another type and back again to be able to remove "extra" data or code. This might be too much of a solution if you need to process many images--but worth a thought as well as the security mentioned in the previous answer.