I got exactly the same problem.
Got the same line of code “<img heigth=”1″ width=”1″ border=”0″ src=”https://imgddd.net/t.php?id=15896232″>” at the end of my website.
I asked the company where my website is hosted about it, and the answer was: Your computer is propably infected.
So I run a virus-scan , and got the same Trojan as ‘afcreatives’ got.
What a coincedence!
I guess this trojan is probobly a keylogger, which logged my username & pass from my computer..but i don’t know how exactly.