The shell command
"/var/www/html/moodle/filter/tex/mimetex.linux" -e "/mnt/moodledata/filter/tex/971509b02ef49c6972fecd1fc84e32b9.gif" -- '\Large \Delta _{pq}^{p}=7520-8620=-1100'
returned status = 1
Image not found!
Please try the debugging script