My Image Garden does not recognize my PIXMA MG7150 printer. I am using Yosemite OS.
The problem that you experience has to do with the driver of your printer. The solution is to get the latest driver for your OS. You can do this by accessing the official Canon drivers download page:
You should pay close attention to the selection of your OS, as other Canon users miss-clicked the correct option and thought that reinstalling the driver was not the solution for them.