Here are some statistics for each of the images displayed on this site for Charlottetown. Such statistics come in the form of histograms which show the percentage of pixels that have a certain value, such as 0 to 255.
All three histograms and their statistics show that much of the images are comprised of darker pixels than brighter ones. For example, by looking at Figure 5.4, one will notice that a high percentage of the pixels are situated to the left of the graphs. These pixels are dark because much of the surface under study did not reflect wavelengths back from the surface. Instead, they absorbed the radiation. This is especially true for deep water bodies. However, Figure 5.3, a histogram for the natural colour composite image, shows a more varied range of pixels values.
(Images for this page are from my F drive, under the folders, GEOG 4440 3.0 Assignment 0, Charlottetown, and Charlottetown Statistics.)