The image you uploaded likely doesn't have sufficient resolution . Remember that the minimum resolution is  120 pixels per inch.
You also need to consider the actual size of the image; for example, if the file's actual width is 10 cm, we can only print it at that size to avoid pixelation or blurriness.

Once you upload an image, it will be displayed at its maximum possible size. You can only make the image smaller; making it larger would reduce its quality.