Yes, you can bring a photo into Sketch to work with. Here are instructions for Sketch 3.4, which now has layers. Open an image canvas in Sketch, and tap the “plus” icon above the layer icon. (On my system, the layer icon appears on the right side of the canvas.) After tapping the layer icon, a pop-up will appear, giving you a choice to add a new drawing layer or an image layer. Choose Image Layer, and a new menu will appear, with multiple choices. If you choose “From my iPad” you can then choose an image from your camera roll.
I hope this info is helpful to you.
Thank you. That was just what I needed.
Hello, Hi, Richardh10267819,
Great! I'm so glad.