You need to get eather chicken wire or cork or string or ribbon what ever you like then hot glue on back strips about 2 inches apart across the back starting at the corner then when done do other corner so the strings cross so you could hang the earrings on them
Darlene: What a great idea! You can remove the back and replace it with thin wood that you either paint or cover with wall paper or fabric. Then, use decorative hooks or small brass nails and attach then to the wood and hang your earrings on them. Or you can use netting or screening instead of wood. Here's a site using screening: https://howdoesshe.com/picture-frame-earring-holder/
Here's a site for pierced earrings: https://www.ehow.com/how_6520190_make-frame-pierced-earring-holder.html
This one looks fab
Attach hardware wire or chicken wire to the back of a frame and hang your earrings on it. It will look similar to what I did with an old cheese grater.