Please note:
1: There have been a couple of studies of the effect of JPG compression on adversarial images. See:
https://arxiv.org/pdf/1705.02900.pdf https://arxiv.org/pdf/1608.00853.pdf
2: This is NOT a 'Voila - Busted!' dissemination. The most straightforward idea for a counter-attack is to include jpeg compression part of the transformations set (T) in the paper. That said, the defender only has to concoct a custom transformation that is not covered in T. For ex, I also found that a scanned paper printout of the image did not retain its adversarial threat (posted on the original blog).
3: This is a work in progress. Github link: https://github.com/vinayprabhu/Jpeg_Defense