Darkle I don't think there's anything special to do in Mapbox. I don't remember if they require a credit card on file or not though.
Then on the extension side the token + the "view exif" permission should enable the map on images with geolocation data. You could check under the exif details whether there is a latitude/longitude for the picture(s) you uploaded. If the exif list is completely empty maybe you have some unsupported exif tags that broke the parser. You could send me a sample image to take a look.
Also just in case you could check no ad blocker prevents the image from loading.
If the map image is successfully generated, you should see the number of images rise in the Mapbox statistics https://account.mapbox.com/statistics/ (it's the category "Static Images API", there might be more categories displayed if you also use the Mapbox account for other things)
An update with new features is still in the works, thanks for your patience 😇