As well as another photo at a different angle and lighting conditions, you may want to circle the area in question to delineate the stain/discoloration.
Was the car delivered this way or did this happen later after you've had the car for awhile? Were you wearing new(ish) jeans or other clothing that may cause dye transfer? Were you wearing shorts and had sunscreen or other lotion/cream on your bare legs? A bit more background information would be helpful.