I hear ya on the gallery traffic issue.  Although, I believe the Mix Medium gallery has at least as high a traffic rate as the Carrara gallery on the average.  Some galleries are quite leanient about what consitutes a valid posting, so don't feel pressured on posting your image elsewhere simply because more than one program was involved in the final image. 

Personally, if I use an item that I'm particularly happy about, I will credit it in my comments reguardless of where I got it and if it was free or not.  I think a fair number of folks do too.       

Irene-