Looking at the Rule34.xxx numbers, this image was obviously created quite some time ago. The numbers at the time of this post are 2795 and 5819 for Panty and Stocking respectively. Not to mention that they've moved to proper Panty Anarchy and Stocking Anarchy tags
A reverse image search gave this post on reactor.cc as a result. In the tags and in the title you can see the name PhishCaek which was the previous handle and Twitter username of phishtickz. They've made a lot of P&SwG art and the style matches, so I'm willing to bet money that this is a match. Their old account was unfortunately nuked instead of renamed (just like their old Tumblr), so the originals are most likely lost.
Also, here is an archived 4chan /a/ P&SwG thread where someone has posted a sharper PNG version.
Nah, being horny as a main character trait tends to have a negative influence on the amount of fanart a character receives.
Only if there's no character of the same tier relevance as the character mentioned. Shimoneta has proven that since back then, with Anna Nishikinomiya, the horniest female character in Shimoneta appearing 158 times here while the main female MC kajou_ayame with only 68 appearance.
