The person inputting prompt modifications may have controlled the larger assets as a whole, but they did not curate the Gestalt of the image. If the input is text that a computer is to output as a literal estimation, then it is data, not art; if the input is data curated by a person who means for a computer to output it as plotted data, such as with a complex lineplot or 3D model or even text as ASCII images, then that can be art.
The person inputting prompt modifications may have controlled the larger assets as a whole, but they did not curate the Gestalt of the image. If the input is text that a computer is to output as a literal estimation, then it is data, not art; if the input is data curated by a person who means for a computer to output it as plotted data, such as with a complex lineplot or 3D model or even text as ASCII images, then that can be art.