The gist of this technique is to render elements of an image so that a viewer doesn't notice everything immediately, therefore delaying perception of the full meaning of the picture until it has been studied more closely. Another word for this principle is "emergence." You may already notice that this is the antithesis of the tendency of many modern photographers in the digital age to maximize the visual impact of everything they possibly can: more contrast, more saturation, everything sharply focused (especially prevalent in HDR imagery). When everything in a picture screams for the viewer's attention, nothing wins; looking at the image is visually exhausting.
In order to build this element of time into the experience of looking at a picture, we need to understand how human beings read a photo - literally what we notice first. The image of the woman in profile with her eyes closed demonstrates many of these elements: in order to take in an entire image, we tend to step back (depending on the size of the image) so our field of vision can take in the entire frame at once. Our fovea, the part of our eyes that sees sharp detail, only really works with what we're looking directly at in a very narrow field of vision, so we tend to notice the center of the frame first - the part we're looking straight at. The further away from center, the longer it usually takes us to scan and notice it. There are no hidden or delayed elements in this portrait; this is a very straightforward image.
What else attracts our attention? In a nutshell, lumosity, bright colors, sharp focus, larger object sizes, human forms, and patterns (repeated visual motifs - see my previous post on this topic). Once we know this about the human visual experience, we can delay perception of certain elements in a photo by employing the opposite of these qualities: darkness, desaturation, blur (through de-focusing or motion blur), smaller sizes, etc.
In terms of color, the most luminous colors (particularly the warm yellow-orange-red family) "pop" or stand out. Less luminous colors such as some blues or purples tend to recede. A great principle to remember is that the size of an object can be in inverse proportion to the luminosity of its color. I.e., small spots of bright colors like yellow or red work well in a sea of blue, but the inverse of that, not so much.
In the image of the man running in the industrial landscape, the building and street dominate the use of space in the frame, yet the saturated, complementary red of the man's shorts keep us coming back to him. (Red is a motif in this image, splashed across the street as well.)
Luminosity: in the "Alpha Dog" image of the woman with the three dalmations, most viewers notice the dogs first. They are bright, their spotted pattern is distinctive and contrasty, and their faces are turned at least in profile to camera, whereas the woman's face is hidden from us. But despite the fact that she is centered in the frame, most viewers don't notice the paw prints in her sweater until later (most likely because they are dark and low in contrast), and then have that "aha" experience of "catching up" to everything the photographer is up to.
The image of the tree under the Manhattan Bridge illustrates the same principle in reverse: the tree and bridge keep demanding our attention over the buildings in the background, because they are sharply rendered with high contrast, whereas the buildings live in a constrained, high-key end of the tonal palette (rendered that way by a blinding blizzard).
Focus: optical focus literally directs the viewer where to look. The smart photographer can exploit this understanding to create useful tension in a photograph by deliberately including out of focus elements. We can "read" expressions even on very blurry faces, for instance, but since blur is almost exclusively limited to photography (our eyes autofocus wherever we shift our gaze), rendering elements blurred introduces great visual tension. Are we supposed to look, or overlook? There may be many reasons to do this: to suggest that something should not be looked at, or cannot be seen clearly, or were an accidental intrusion into the frame (riffing on the snapshot aesthetic). But as human beings are meaning-contructing mechanisms, the viewer cannot help but examine every clue in an image, and if we trust the photographer's craft, then we must assume that everything in the frame is there for a reason. I am also of the opinion that good art, the kind that stands up to repeated, long-term scrutiny, raises interesting questions; it does not provide simple answers.
Most viewers notice the woman in the mask first; the fact that she is the largest figure in the frame, carefully framed, well-lit, her attention obviously engaged with someone off-camera, and wearing a mask that seems unusual in context all contribute to this. But the fact that she is rendered out of focus is a clue that she is not truly the subject of the image; it is in fact the smaller face of the woman lurking behind her dressed as a cat, and making a rather catty expression. Hopefully the viewer "discovers" this smaller figure after a moment's delay, and enjoys inferring why their expressions might be as they are.
Size: in the image of the house sinking into the slope of green grass, the dog is typically discovered a split second after the initial look; she is simply very small in the composition, nearly silhouetted, and off-center, but she also seems to be regarding us, and is the only living figure in the image. The diagonal shadows help lead our eye to where she is standing.
Keep in mind that the size of your print can be a major factor in the way viewers perceive the image. Thus, looking at tiny, low-resolution JPEGs online is far from an ideal demonstration of these principles.
To summarize, don't put all your cards on the table at once. Reward those viewers who pay close attention. We are not delaying complete perception as a gimmick; a well-constructed image will exploit the way human beings read an image to create that rewarding experience of discovery no matter how many times they look at the image. Those are the kinds of images collectors like to hang on their walls, and are excited to show their friends. They endure; they don't exhaust.