Sharing a thought about subjects

When reviewing photos here in the forum, I often think, and comment, "what is the subject of the photo?".  

Take the following photo:

Pretty boring. What is the subject? Why would a buyer want this photo? How would he find it over the hundreds of thousands of  other ocean shore photos? My possible keywords are pretty limited.

One way to get around this delima is to photograph and save subjects that I can use in photo compositions with my "boring" photos. This gives me unlimited possibilities to upload single photos a number of times to my portfolio. This increases my chances for selling.

For instance this photo:

(Keywords: bird, seagull, flying, sky, wings, spread ...)

Useless, boring and poorly cropped. Only a few details in thge sky. 

So, by cutting out the seagull, I can compose it with other photos to make them all sellable.

The seagull can be used an unlimmited number of times.

(Keywords: bird, seagull, flying, sky, wings, spread, soaring, high, clouds, blue sky, whiteclouds, sunny ...)

Alone by having thge seagull fly into the photo and adding a detailed sky I have a sellable product.

(Keywords: bird, seagull, flying, sky, wings, spread, river, pier, wood, dike, shore, sand ...)

Another option.

And here another:

(Keywords: bird, seagull, flying, sky, wings, spread, pier, storm, dock, waves, rough, ocean, sea, stormy, cloudy, light, beacon, lighthouse, warning, light beam  ...)

Notice how each photo increases the possibilities I have for adding keywords? This makes my photo "findable" and increases my odds of selling a photo.

Get my point?