Reference : http://askmichel.icoder.com
When you have a Contact-Form on your site, you are having problems with spam submissions to the form. Unfortunately, spammers have programs that find forms on the web, and automatically fill them out with spam messages.
The standard way out is the use of captchas. However, there are bots, that can recognize simple captchas in a second. Let’s review ideas of Form-Spam bots blocking without captchas.
Reference : The Joomla! ® Community Magazine
Joomla! is often bashed by unknowledgeable people as insecure. How little they know! The fact is that no system is airtight, unless you do your part to secure it. Most people coward away hearing as much as the word “security” itself. You don’t have to! Securing your site is rather easy, if you know what, where, and how it needs to be completed. This article may only scratch the surface, but will provide you with enough advice to perform a major upgrade in your site’s security in a few, easy steps.
Reference : موقع رافع نت التقني
Pixlr Editor : online application
Gimp : you msut download it.
Adobe Photoshop Express : online