If you are not seeing text on your secure code or secure image, there is a proble with the fonts on your system.
Try looking at your logs to see if this is the case, you will find a line like this:

convert: unable to read font `/usr/share/fonts/default/Type1/n019003l.pfb’

To solve the problem you should install the fonts, in the shell type this:

sudo yum install ghostscript-fonts