The 4th Estate Project, which tracks media coverage of the presidential campaign, says the mentions about Romney's character started to move in a positive direction after he selected Ryan.
Discussion of Ryan’s Character Has Been Good for Romney
From August 9-12, positive statements in election coverage about Romney’s character from newsmakers outside of the campaigns increased from 10% to 38%. It briefly surpassed negative coverage toward Romney’s character by 20%, as negative sentiment dropped from 58% to 18%. However, this quickly changed as positive coverage toward Romney’s character dropped below negative coverage just one week later.
This brief spike in positive coverage toward Romney’s character was driven by Paul Ryan’s likeability. Many newsmakers outside of the campaigns discussed Paul Ryan’s character in a positive light, which helped to bump Romney’s image.