Once you've found a usable image, print yourself a copy of any images with labeled parts. Then use a paint program to white out the labels and print that copy for your child. Your child can label or color the image and have both art and science lesson at the same time.
Baby boy clip art is the most wonderful way of splashing your work with images that you think can do the magic. It is also the cheapest and the most colorful way of doing so. Most of what you will find will be free printable art.
So for that reason, a lot of people turn to the internet when they are searching for clipart designs to spruce up their digital creations. Sometimes you can find these easily and they're free and really well designed. But sometimes, honestly, not so much. A lot of the people who run free Xmas clipart sites have a tendency to put up a lot of ads that show up in the places where you are trying to download clipart.