How will we be able to check whether the pixel perfect images are actually pixel perfect, or whether our minds simply trigger the (binary?) signal "looks crisp

How will we be able to check whether the pixel perfect images are actually pixel perfect, or whether our minds simply trigger the (binary?) signal "looks crisp to me"? I've oftentimes tried to recreate such a vivid image, either in a drawing, or simply in my mind, and I've always failed. The vivid image always fades away upon closer scrutiny.