https://help.sketchup.com/images/fg114_1.png
Manually digitizing the raster data by sketching over the image will lead to extrudable vectors.
Vector data of SVGs cannot be imported natively by SU but you can convert them to the DWG/DXF format (= industry standard for 2D CAD data) by using free Inkscape.
more info at:
• SketchUp Help Center : Importing and Exporting Image Files