Thank you ! Actually I didn't even expect someone would notice it ^^
I made the spiral background with paint (yes with paint xD) and then i used a software called picnik (which sadly is not available online any more) to make the zooming effect and to add the text and the details
You can use this website : www.picmonkey.com/
, it's not as good as picnik but you can still use it to get nice colours and to use the effect "zoom focal".
I hope this helped you !