convert:not authorized `aaaa` @ error/constitute.c/ReadImage/453

I want to create a captcha pic by use convert from ImageMagick. And I follow this, but there are some problem . Input In my linux shell: convert -background white -fill black -font FreeSerif-Bold -pointsize 36 label:’adfgh’ ./test.png The Error is: convert:not authorized adfgh @ error/constitute.c/ReadImage/453. convert:missing an image filename ./test.png @ error/convert.c/ConvertImageCommand/3015 My ImageMagick: … Read more