I am importing a jpg to use when I draw a shape for a shoe sole.  I want to lighten the background image so I can see what I am drawing.  In other programs I have used it is possible to lighten, like change the line image of the background to a light grey color.  I am new to this and have tried the manual and forums, but can't figure this out.  I looked to see if there were choices when I import the image but can't see any. I don't want to trace because it creates too many nodes and for this fairly simple shape it's always easier to just draw it with the Bezier tool.  Anyway, I think there is a way to do this  and I need this ability often but I am a newbie to this. 

Select the jpg and lower the opacity as needed.

Thank you, got it, I knew it was probably something simple, but that's the problem for newbies!!