Print out the images or have them professionally printed. If inkjet, spray with clear acrylic sealer or hairspray on both sides.
Paint the canvases with the colors of your choice and let dry.
Spread a medium layer of Mod Podge down on the canvas and smooth the design down to the top. Let dry for 15 - 20 minutes.
Put a top coat on the image and then the entire canvas. Let dry completely before hanging.
Notes
If you are having a hard time smoothing the image to canvas, turn over on a non-stick work surface and smooth from the inside. This helps since canvas is flexible.