All eggs have a noticeable white spot. An infertile egg just has a white spot or a smudgy white spot. A fertile egg has a white spot with a clearly defined ring around it. It almost looks like a bullseye. That's how you know it's fertile.
I don't see a ring in the pic, but there is a bit of a glare so it's hard to say.
I don't see a ring in the pic, but there is a bit of a glare so it's hard to say.