A long time ago, in the same old galaxy we got today, people could not communicate. Then grunting was invented, and civilization took one mammoth leap forward. After eating the mammoth, our ancestors developed tools with which to pass ideas along in the form of drawings. It turns out that the writing was on the wall: eons later we continue this practice; only the tools and techniques have changed. The puny human brain still likes pictures.
The written word has proved to be an indispensable means of disseminating information. It is by all (written) accounts the cornerstone of civilization. Moreover, there are certain concepts that just cannot be easily conveyed in a picture; concepts such as "concept", "written word", or "remedial algebra".
However, for sheer speed of communication it's tough to beat a photo. They are great for delivering certain meanings, such as:
I don't need to describe a military airship that will crash because it's rotors aren't moving... you knew it in an instant, probably before you started reading this, right?
While photos will never supplant good writing, as technology becomes more accessible it will be common for people to use them in their communication. This is a good thing, because this blog would be totally boring without photos. Especially since it's about photography.
As we acquire the photographer's tools we learn ways to deliver the same meanings with different styles, and the same styles with different meanings. Just as words can generate imagery in the mind, so can a good photo elicit words.