Copyright laws have a standards for minimal creativity needed to create a copyrightable work. You don’t have to be very creative to qualify, but you need a minimal amount. There’s no good reason to think the US copyright office will not apply these same standards to AI art prompts.
The US copyright office specifically lists “listings of ingredients or contents” as not sufficiently creative to qualify for copyright protection. This is why there is no legal recourse within copyright to prevent someone from copying the ingredients and quantities of your cooking recipe. If the prompt you give your AI is more than a list, you will not have a copyrightable work. For example, if you open up an AI image generator and type: “paved road on a cliff-face overlooking a pine forest,” the resultant output would likely be ineligible for copyright because the prompt was little more than a list of the image’s contents.
If your use of AI is creative enough to reach the level of “minimally creative” in the eyes of the US copyright office, the work is copyrightable.
When taking a photograph, you chose the settings, you chose the framing, you chose the equipment. That is enough to be eligible for copyright, unless the shot was taken by a macaque or a grizzly bear.