White background is tinting when chainging PDF to JPEG in Acrobat XI Pro

I often will use the "Save as Other" function in Adobe, to change documents in pictures.  Recently, I noticed that when saving a document, the white in the background comes out tinted yellowy green.  Ofent these may be text documents originally created in word and then saved in Adobe.

I did get a  new computer, and had to re-download Adobe onto it, so perhaps it is a setting that I am missing?

I tried to use an online PDF converter (Zamzar) and it does NOT seem to have the same problem, so it is my adobe program's conversion of the PDF that is causing the issue, and not the PDF file.