Hi OP. Upload the photo to the internet somewhere, e.g. https://imgur.com/; copy the image's URL; edit your post's text (click the edit link); and paste the URL here - voila. Adding any other info you know about your great grandparents background would probably be helpful to provide context for the photos.

It's worth considering that it may be better to head to /r/genealogy to learn about how to find the family history of your great-grandmother, rather than to ask people to guess based on her facial features or other aspects of her appearance.