The way image can tell a story has various forms. If you are tired of bar plots or trend plot, take a look at this presentation.
Most of the time, when we thought about frequency, we thought about how many times per second. However, in the daily life we rarely used frequency to define a spatial relationship. However, the concept can be played in the simplest way to give very interesting effect... To say....the basic concept of "zoom out" and "close up". High spatial frequency represents the abrupt changes in the images such as the edge or corners , and low spatial frequency represents the overall shape and orientations of the subjects. Our visual system has the ability to differentiate the spatial details with a threshold frequency. As a result, below the threshold, the image details will not be discriminated by naked eyes (If you have the chance to listen to the neural recording for different visual stimuli of various spatial frequencies, you probably will even be able to tell the threshold by the sound ).
The most common case you should notice is the classical oil painting, where brush strokes are meant to be placed with various styles, yet to produced an overall contrast and brightness that resemble the scene when the piece is viewed from some distance away (I figure there are still many who got very curious why painters just love to stop in the middle and step away from their work to exam their paintings). However, if you have a close up of an oil painting, the strokes probably can be mean nothing in terms of shape or shade, unlike the traditional asian or Mediterranean paintings. In this way, low spatial frequency dominates the information of the image, while the high spatial frequency demonstrates the styles of the painters (specially for the impressionists, such as Van Gogh ).
To even further demonstrate the concept, I have a new drawing that I did using photoshop and digital tablet. You can try to compare the photograph taken, and the drawing to see the effect of spatial frequency.
A more fun example is probably the "famous" Einstein Marilyn Hybrid image.
Thinking about generating your own hybrid image? It is actually not that hard with photoshop.
1. Get two black and white face images with their face aligned (better to use images with dark backgrounds);
2. Blur one of the image with Gaussian filter with radius of your choice (this depends on how far you want to see the hidden image from far away).
3. Set the combine mode to screening and adjust the top layer's visibility to roughly 90%
4. Combine layers.
Now you should have something very similar.