If you have to use a JPEG, then I was under the impression that 676px was the widest image size we would be allowed. (I sent a JPEG of this size). If possible, use the larger JPEG that I also sent, "CAB Infographic 19 - 2817px across.jpg"

But it would be MUCH better if you could use an SVG. Here is the JPEG, and below I will put the SVG.