I'm using the auth.settengs.extra_fields to add an extra upload field for the user to upload an avatar, how can I add an IS_IMAGE validator to the upload field so that the user can't upload random files?
Also, how would I add an IS_ALPHANUMERIC to the built in First name and Last name form fields? Right now there are users registering with names like "!@#$%^~" and some such... Thanks!
