The gallery is for posting and commenting on images. Allowing one user to "showcase" their work with "Rate my____" threads or collection-comment threads means we need to open the floor to everyone for the same. And we don't intend to do that.
Please showcase your work and collect comments -IN THE GALLERY-.
It's simple enough to convert a file type. Ask in the graphics or tech support section if you need help.
That's what it's for.