Besides being the role of female actress Juliette Lewis in the Oliver Stone film "Natural Born Killers" there is more than one artist with this name (see links in the Wiki sources):
These are photos from concerts where Mallory Knox played, so they may be of other bands that played the concert as well.
Canterbury / Mallory Knox / Scholars Dec 7, 2012 Sheffield, England, United Kingdom Uploaded by Hxrdtimxs
Reckless Love / Empire Of Fools / Mallory Knox Oct 23, 2012 Exeter, England, United Kingdom Uploaded by Josh King
Reckless Love / Mallory Knox / Exit State Oct 15, 2012 Manchester, England, United Kingdom Uploaded by Mark Hutchinson
Reckless Love / Mallory Knox Oct 6, 2012 Newcastle upon Tyne, England, United Kingdom Uploaded by Robyn Daniels