Here's a quick tip: Just enter all characters separated by spaces....

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

...and save the resulting image locally. You now have a nice "template" that you can easily use to cut and paste to create any combination you want "offline". Do the same for lowercase...

a b c d e f g h i j k l m n o p q r s t u v w x y z

...numbers...

1 2 3 4 5 6 7 8 9 0

...and symbols...

! @ # $ % ^ & * ( ) – = _ ~ ` { } | [ ] ; ' , . / : " < > ?

...and you have all the images you should need.

The only caveat to this is that the actual letter colors are preset, so if you spelled, for example, the word "class" it would be all in blue. Of course, many image editors would let you tweak the colors as needed....

the class is example is not true :/

and by the way.. if you enter

AAAABBBBCCCCDDDDEEEEFFFFGGGG
HHHHIIIIJJJJKKKKLLLLMMMMNNNNOOOO
PPPPQQQQRRRRSSSSTTTTUUUUVVVV
WWWWXXXXYYYYZZZZ

you even dont need a grafic programm that supports Hue/Saturation :/

[Linebreaks added – Tony]