"CollageIt is a very nice and useful photo collage utility."
- Soft32
" It's a great photo collage software! A very, very fast and simple photo editor."
- Benjamin Glettenberg
Choose Print toolbar button to go to printing mode and to make print settings (Printer, Copies, Pages).
The following window will pop up when the print paper you use does not match the collage size you have set.
You can set Scale as Fit to Page as a solution.
Upgrade to CollageIt 
Download CollageIt for Free