No you're not under DNS attack. What even made you suspect that in the first place? What makes you think this is some security related attack in any case? It sounds like a bug on your site only, not of use to anyone else, and certainly not security related.
DNS lookups return only one IP for me, so all requests go to that IP but are handled differently from time to time. This makes it completely unrelated to any possible DNS issue. I am curious how you came up with the idea that it was a DNS attack.
The site was hosted on free hosting, all kinds of random events can occur there. Here it (for some reason) displays the (presumably) original file sometimes, and an error page at other times. I'd say their systems are not running synchronized or something, you should try again later. Or you just contact your host like you are supposed to when you have problems with your host.
For information's sake, it seems to be cookie-based. When I F5 or ctrl+F5 the page it shows me either the image or the webpage. It happens to be 50% of the time that I see the image, but it's not probability-related. It simply shows the webpage every other time.
When I open the page in incognito mode it will show me the image. Closing incognito mode and then opening it again, shows me the image again (this erases cookies or other set data). I haven't looked at the connection data, but that's what makes me think that it's cookie-related.
To resolve this, just ask the host. This is not related to security and thus I voted to close the question.
Edit: Saw your comment about your load balancer. Interesting combination, load balancing on free hosting. Perhaps include more details so that we can understand what might be going on, or what makes it a security question anyway?