Image Issue – WordPress is creating 1px x 1px images on some of my old posts

I noticed this yesterday and I have just uploaded wordpress to 4.2.2 and updated all of the plugins and the issue is still happening.

WordPress is creating 1px x 1px images in the media folder like this http://iheartpgh.com/2006/01/25/pittsburgh-is-paris-says-denver-columnist/rp_reblog_c-png-3565/

All of the images have rp as the beginning of the name.

Any idea what could be causing this?