2 of 2 people found this helpful
Optimal format would be png that way you can have a transparent background and it would blend well with whatever banner colour you've set in the style editor within HEAT.
I've also noticed that 220x60 is the best pixel to work with, which from the looks of it you're already there. Have you tried just previewing the image on its own though? I generally use GIMP (open source) to make the logo alterations I need.
Sent from my iPhone