Author: Brian Barnes
MDL-48265 feedback: Added alt text to ghostscript test image
http://git.moodle.org/gw?p=moodle.git;a=commit;h=a7d7354c85deabc877e695ba5209cc688dd7ac80
http://github.com/moodle/moodle/commit/a7d7354c85deabc877e695ba5209cc688dd7ac80
+ 2.8 en [gsimage,assignfeedback_editpdf]