Need help on digital image for academic paper

[Ruly Darmawan <rdarmawan@xxxxxxxxx>]

Dear all,

I need help for my current situation.
I wrote an academic paper which has been presented in January.  In this paper, I did put a digital image downloaded from internet (http://www.livewithbits.com/).
Now, I am willing to use the same image for another paper.  When I re-trace the resource for that image, I can't find it anywhere.  I can't even find the previous website.
My colleague said that the website was probably no longer exist. Or, even worst, it never exists.  He said that the website might be sub-domain or "the shadow" of another website (Actually, I do not understand this technical domain).

I can omit that image in my next paper.
But, what should I do with my previous academic paper?
It has already been published and has been documented in a proceeding...

Although it was written in the website that the images are copyrighted-free, what if this statement is false? 
What if the images are taken from another website and they are not copyright-free?

I really, really worried about the infringement of digital properties here.

Please. I really need help to clarify this situation.

Thank you very much.

Regards,
Ruly Darmawan