GAN to generate a custom image does not work
Generating text as an image is extremely difficult and I have never seen a GAN applied in the image space to generate pages of text. The reason this is so hard is because of the way in which text is perceived by humans and the way a GAN works.

Humans read arbitrary symbols which are sequenced from left to right along the same line and combined into rows. Moreover, these symbols are combined into groups which represent words. This is extremely complex. The symbols must be intelligible, the words must be real ones as invented by humans. Lastly, the combination of words into sentences need to be logical and follow guidelines of human language. And even FURTHER the sequence of sentences must be coherent to transmit a message.

A GAN operating in image space will try to learn the distribution of the training set in a pixel-wise manner as that is your inputs. The distribution of the pixels will not effectively be able to group characters together in a logical manner, and the words will not be real, and the sentences will all be nonsense. You will most likely end up with blurry lines of random looking symbols, kind of like a zebra print.

Another problem is the amount of data you have. Even if this problem was possible with a GAN you would need tens of thousands of instances to train a GAN effectively. 



What I suggest

I suggest to read the texts that you are training with and use this data to train a LSTM which has been shown to be very effective for generating language. But, be warned even with the best LSTMs you rarely get text that can fool humans into thinking its real.

The LSTM will provide you with your text.

Then you can train a GAN to generate the characters of the alphabet and you can use this generator to print out the text that the LSTM generates.