Hi! You actually have the ability now to add text on top of an image in the editor:
1. Click on an image placeholder and either upload your image or select it from your library. 2. Click Edit this image. 3. Scroll through the options along the popup box's top, and select the Text button.
4. A text box will be inserted atop your image, and you can start typing. The black box around the text will go away once you apply it.