Hi Ann,
Thanks for your question and thanks for using Crio Pro WordPress theme!
I just reviewed your site and it looks like you’ve already managed to find a solution because I see that the default image has been changed. For future reference this image is applied to the entire section as a background.
So in order to change it you would need to select the overall section itself and click on your image to bring up the element options then click the image icon located towards the top of the page builder and select Section to open the background controls.
Hope this helps. Please let us know if you have any other questions.