digital photography printing question for Mac?

I want to enlarge some photos. I am using canon photo studio and iphoto programs, on my Mac. The images when i print them come out too small but i can’t figure out how to make them bigger. Please help!
thanks for your answer Jeannie. I see the set sizes, but don’t see the possibility of making a custom size.

Good question. I don’t find iphoto to be especially user friendly, especially to someone experience with photoshop. I looked in the Help menu, and what do ya know! It told me to do the following:

Choose the photos you want to print, make them into a project or album/event.

Click on one and choose File, print. In the print dialogue box where you choose the printer you can also choose the print size (lower right hand corner) from a pull down menu. You can choose a series of presets or customize and print to whatever size your heart desires.

have fun