I have Standard SolidWorks 2016 SP 1.0,

I have traced the outline of a flat item on to paper with a pen and have scanned the item.  I have not yet saved the scanned image because there are many formats I could choose from (.jpeg, .gif, etc.).  I want to import that image into a part file and trace it in sketch mode.  I do not have Autotrace (as far as I know) so I would trace with ordinary sketch tools (line, spline, arc, etc.).  How do I get from the scanned image to a traced sketch so that I can make that sketch into a sheet metal part?

What is the best format for saving the scanned image?