There is an edit box on the main screen, any file extensions shown there and Super printing thingy will use the windows image viewer to try and print the file, not matter what that extension is associated with. If .tiff is shown there, try removing it and see if windows tries to use anything else to print. o, then associate with something better to print.
the problem is, someone else was having the issue earlier that hat their files were associated with was then coming up with the print dialog. It seems to be a no win situation, unless you can associate with something half decent.
I use Paint Shop Pro, and that seems ok....
I'll look and see if there is a way pf printing actualy size with the image viewer... No doubt someone will come back later and they want to print full size with it!!! Ho hum...