MQTT Camera payload - Unable to serialize to JSON error

Trying to setup an add-on with MQTT Camera and can get the image to load correctly, but can’t open “MQTT INFO” under Configuration > Devices > (MQTT device) and get this in my logs:

Unable to serialize to JSON. Bad data found at $.result.entities[0].subscriptions[2].messages[0].payload=b'\xff\ ….

Do I need to send the image bytes as json?

you have bytes in your payload, which cannot be serialized to json.
take a look at this: How to send camera_image to MQTT Payload? - #7 by robmarkcole