Many churches use podcasts to publish their weekly messages, and often they have a specific logo or image that they would like to display with each sermon. The app can most certainly display your custom image with your audio file, but in order to do that, it must be attached to your RSS feed. Contact the website developer who set up your RSS feed, and ask them to change it so that each file has a custom image attached to it as well. It should be simple for you to upload the weekly image at the same time you are uploading the weekly audio.