There are two main graphic styles, bitmap and vector. Bitmap graphics, which are created by filling pixels, are used for engraving on the laser cutter, but don't scale well. Vector graphics are the result of mathematical instructions and can scale without losing resolution.
There are many tutorials on the web for vectorizing graphics, I've put a link at the bottom of the page for you. After you watch it, find a bitmap graphic online (.jpg is the most common extension you'll be looking for) and import it into Inkscape to vectorize.
When you are done, email the file containing the original bitmap and the new vector graphic to email@example.com.