Typically we don't grant permission for the actual logo, but creating your own fan art is usually acceptable.
put simply:
If you drew the image it's ok.
If you used an official image from Stardock, it's not ok.
PS: Logo lizard was drawn by hand by me, looking at the picture, then reduced and transferred to four colors - Two green; red and yellow. - Any such picture will look like after such operations almost identical (* More so under such small size
Sounds like it's ok to upload 
