Author: Brian Barnes
MDL-48265 feedback: Added alt text to ghostscript test image
http://git.moodle.org/gw?p=moodle.git;a=commit;h=25fd8e07782bcd2439bdfde0437b70a0dc47b933
http://github.com/moodle/moodle/commit/25fd8e07782bcd2439bdfde0437b70a0dc47b933
+ 2.9 en [gsimage,assignfeedback_editpdf]