Also if you have normal vision, try moving the monitor or your phone away from you. You must observe Abraham Lincoln.
How does it work? Your vision is the only thing that determines this. If the screen was further away, it would be more difficult to focus on fine details, such as lines. As a result, a person would only see President Lincoln.
When you make the image smaller, you will be able to observe President Lincoln. This is also true. Once the image is small, you won't be able to see the fine lines.