Using SolidWorks 2015 SP5.
Here's a screen grab of the drawing.
here's a screen grab of the saved-as PDF:
notice the Ellipse Logo is missing from the PDF.
Try printing it to pdf -not saving.
This might be a workaround.
Is the logo on a non-printing layer?
Select the image and see what layer it's on and then open the layer dialog to see it the layer's light bulb is lit.
Do any of your view boundaries overlap the logo? This can sometimes obscure an image when saved to PDF. It also matters whether it a 'Sketch' picture or an embedded object (i.e. copy and pasted from paint for example)
Retrieving data ...