Can you smile in Singapore passport photo?

You are not allowed to smile when your photo is taken for a Singapore passport. Only neutral expressions (with no teeth showing) are accepted.

What is the size of photo for ICA PR?

You need to ensure that the photograph submitted is 35mm wide by 45mm high, and does not have a border around it. For submission online to the Electronic PR (e-PR) portal, the photograph has to be in a digital image file, sized 400 to 514 pixels, no larger than 1MB in either JPG or JPEG.