Here's the problem:
The equation for time dilation is T = t/sqrt(1-v2/c2)
with c being the speed of light
In your example t = 2 days, v=c, and T would be the time measured on Earth.
But if v=c, the above equation reduces to T = 2/0 days.
2/0 has no answer, it is "undefined".
Now in reality, we can know how long it takes light as measured by the Earth to travel some distance. For example, we know that it takes roughly 8 min for the light from the Sun to reach the Earth. So really what you are asking is how much time would the light measure?
That in equation form reduces to 8 min = t/0
But we have run into the same problem, there is no time period that, when divided by zero, gives an answer of 8 min.
The upshot is that it is meaningless to talk about how much time is measured by the light. In physics parlance, you would say that light, or anything else that travels at c, does not have a valid inertial frame from which to make measurements.