Since you specified "an image", I'd rule out any spectral information from this attempted answer. An image in the following context refers to a grayscale image taken at a narrow band filter/wide band filter/ a single wavelength 2-D image with some decent spatial resolution. However for the following to make sense, I'd make myself the luxury of having more than a single image, ideally a sequence of images of the same object/ planet acquired during a short period of time (hourly/ daily).
History tells us that early scientists were able to decipher the rotational period of objects, ex. Mars by looking at them through telescope. Basically, you follow a surface feature (why I said decent spatial resolution above) that is sticking out and observe when it returns to its original position and the time elapsed will be the orbital period of the object observed. Since you did mention "an image", this calculation could be made more precisely using a computer. If you check out this wikipedia link, you'll notice some surface features on Mars, referred to as albedo features due to their differences in brightness, similar to the red spot on Jupiter, that you can also follow as it rotates. In the case of Mars, this led to the detection of its polar caps which fuelled a lot of debate and development of science on Mars over the years.
One could also potentially determine the tilt of the rotation axis of the object using this same method. So you look at the path traced out by the surface feature of interest during its rotation.