gifmaker.meは安全ですか？

I created a banner but after I cleard the cache in firefox I was still getting a connection back to this site. After I deleted the image I created the connection stopped. I do not know exactly what information was being sent back to this site from the image I made, but as they say if something is free on the Internet then you are the product. I have a linux system installed and I noticed the persistant connection using "Etherape", a network monitoring program. Also Note, after I first made and save the image I got a warning from firefox that I had more than one page opened when I tried to close firefox even after all "Tabs" were closed.