File made to specific aspect ratio then uploaded to Facebook "Cover Photo" Page

I need assistance to modify a PowerPoint slide to either a png or jpeg photo. Then, I need the jpeg or png to fit and look presentable in a "Cover Photo" on facebook. Here is the help section of Facebook's site.

https://www.facebook.com/help/125379114252045?helpref=search

Must be at least 399 pixels wide and 150 pixels tall

I have uploaded the Powerpoint file. I've tried converting to a jpeg and then resizing via http://resizeimage.net/ but the uploaded photo doesn't look correct. It looks grainy and fuzzy.

https://www.facebook.com/CDCR-Feeservice-1134267033278366/

It there is a way to show the same content but maximize the space on the cover photo I'm open to that as well.

Once we settle on the job, I'll send along the user name and password to facebook account.