I agree with Stephanie. When I want two pictures side-by-side I use MSPowerPoint.
Make sure that if you use someone else's image that you have the right to alter the image. If it says no derivitives, you may not alter.
But otherwise, put the two photos side by side in PowerPoint and save the two as one picture. Then you can use this one picture in full width -- it will look like two pictures side-by-side.
Remember to add the source to BOTH images in the "Source" box when writing your hub. And don't forget to acknowledge use of the pictures with both photographers.
Doing this is exactly like making a PowerPoint slide for use in your hub.
Hope this helps.