There are many ways to trace an image from your phone. The simplest way is to place a page over your phone so that the light from the screen allows you to see the lines of your image underneath. You can carefully trace along these lines taking care not to scratch or damage your screen. There is also a multitude of tracing apps available that you can download to your phone, or you could simply print out the image and use any other tracing method to transfer it to your canvas.