Regardless of your evolutionary/behavioral standpoints, everyone can agree that if one takes a picture of only an object, one is displaying the object. But if one takes a picture of oneself and the object, one is no longer simply displaying the object, one is displaying oneself displaying the object. However, it seems that many of the female gender (and also many men) do not fully understand the conceit that when one adds oneself into the equation, the picture changes, as with the objective.
There is truth with this, you’re right.
There are some underlying forms of conceit that cause the photo to be taken in the first place as opposed to it being taken in any relevant manner. Like, here’s just the object! Or here’s me actually doing some action (that makes sense) WITH the object! As opposed to, here’s the object that just makes an excuse for me to show off my face! And in a lot of the cases, the people commenting on the picture don’t even notice or comment on the object itself that warranted the post in the first place. This self promotion and displaying is true of both guys and girls but girls tend to have a notorious reputation for posting these types if photos in excess.
It’s good to be aware of these motives and this is just another perspective in which you can be conscientious about how you portray yourself to people though social media outlets.