If you're willing to compile it, Aseprite is a great option as well.
check my website for the latest tips - always updating with new content!
Antarctic Time UDK
A work-in-process of a project created by in Anton Migulko. He attempted to create physically plausible shading in Unreal Engine. He also realized his thoughts about data sharing on big levels.
© anton migulko, 2015 https://vimeo.com/antonmigulko