I'm currently optimizing a website that is using some PNGs with odd sizes like 263x263. Seeing that JPG has some limitations when dealing with resolutions that require MCU-blocks (minimum coded unit) with a size smaller than 1, I was wondering whether PNG suffers from any limitations of such sort regarding unorthodox resolutions that aren't a multiple of at least 2, such as lower compression or compatibility with devices and browsers.
No, the PNG format does not care at all whether width and height sizes are odd numbers. Each line has its own "filter", and the concatenation is compressed as a single stream. There's no reason to try to make width or height even or "nice" numbers.