Eh, crescents and checkerspots are somewhat challenging to ID. They're incredibly variable and can look like each other. For me, I use the row of dots on the hindwing to know for sure it's a crescent; checkerspots never have the dots, which, unfortunately, makes it confusing to remember. A funny thing about these butterflies, I find IDing them on the wing much easier to do than from photographs. The crescents are smaller and a bit more erratic in their flight compared to checkerspots.
I have a question for you: Does anyone know the function, if any, of the colorful antennal clubs often found on various insects? This discussion came up on my black burying beetle post.