Graphics for a website

I need a graphics for my website. It must be a file I will include at the top of my landing page and in the brochure. The graphics is related to the project below: It's a web app that interact with an Access point. This access point is provided with 3 wireless interfaces. 1. For private use 2. For guest use 3. For child usage with parental control. The image must return the sense of these three points. I like a graphics like a cartoon. Here an example of something I like [login to view URL] It can be returned as png file, but I would like if it can be returned in some vectorial format.