Board Thread:Support Requests - Getting Started/@comment-26075901-20150204213632/@comment--20150211230531

I don't think you can update your avatar through mobile devices. I know a few friends who has this issue, and they ended up having to do it on a PC. Another common issue is your image is too big in file size. It has to be under 500KB.

Hopefully Wiki got back to you and helped you out.