Should I upload a photo for job application?

I am filling out an online application for an RN job. In additional to uploading my resume, there is a space where I can upload a photo of myself. It says that this is optional. Should I upload a photo? If I do upload a photo, should I choose a smiling photo or a more serious -looking photo?

Thanks for any advice!

It might not be a bad idea if you're "ideal" looking and it's a very professional photo. I'm imagining some hapless fool uploading a duck-face selfie and I'm cringing a little. I'd also consider whether the application is direct or through a third party. If it's just a third party application feature, the hospital may have no interest in your photo.

I vote for smiling if you decided to do it.