This makes sense from a technical and legal perspective.
Merely viewing Web images of child pornography does not, absent other proof, constitute either possession or procurement within the meaning of our Penal Law," Senior Judge Carmen Beauchamp Ciparick wrote for a majority of four of the six judges.
"Rather, some affirmative act is required (printing, saving, downloading, etc.) to show that defendant in fact exercised dominion and control over the images that were on his screen," Ciparick wrote. "To hold otherwise, would extend the reach of (state law) to conduct — viewing — that our Legislature has not deemed criminal."
Distributing, storing, taking such pictures is still illegal. However, if you merely accessed a site with such images, or someone accessed such images on a machine owned by you and resulted in them being cached, you cannot be prosecuted. This makes sense. Having laws that ban you from seeing files that are on the public domain is ridicolous.