I guess I am not sure what you mean because all text is displayed by use of images. I mean, how else can you display text. There are methods you can use to change the font type, style and size. It sounds to me, however, that you want to add your own character set and use it. Tell me I am wrong, please.

By 'image' I actually meant the use of a .png file to emulate real text. You are correct. I want to add a certain character set (not my own) and use it... is it impossible?

Not impossible, but could be tricky. You would have to create a one to one relationship between the standard character set and your new set. Then, you will have to apply each character used from your new set to an image, one by one, side by side, to create the text string. If the characters are not all the same width, you will have to keep track of where you need to draw the image of the characters on the main text image.

No (maybe I mis-understood you). There are fonts in Java and you can set the font (type, style, and size) for any GreenfootImage object using any of the standard fonts accessible through java. Please refer to the Font class API for more information.