Use rawurlencode() on the provided default image if it is a valid URL.
Use rawurlencode() on the provided default image if it is a valid URL.

Fixes #1 - thanks to @jiripudil for reporting this problem.
For the curious, as to why this does not use urlencode(), please see: https://github.com/damianb/gravatarlib/pull/1#issuecomment-2066582

thomaswelton/gravatarlib,damianb/gravatarlib,emberlabs/gravatarlib,MehmetNuri/gravatarlib