Integrating images into text files (or vice versa)

Question

Hi,
Im wrting a software that uses normal images (.png, .gif, .tif etc) and adds labels to them. So naturally, I have the image file and the file that contains label info. Is it possible to include image into a text file along with the label info? I could write the image pixel by pixel but I want to have the compression of PNG (or GIF) if the user is using those types of images. I would prefer not to have two separate files which is why Im asking.
Thanx.