For reporting violations, the only information that I can find is this brief comment in the Help pages' FAQ on photos:
If you need to completely delete a photo immediately because it contains offensive or illegal content that violates our Terms of Service, e-mail info@wikitree.com. This should only be done in emergency situations, e.g. with inappropriate photos of children.
In the case of modern map data, I would recommend that WikiTree users use OpenStreetMap. It would also be prudent and kind to first make a replacement image whenever possible, prior to reporting the offending version or asking the original contributor to remove it.
OpenStreetMap explicitly allows for reuse of their data, provided that appropriate copyright and licensing is included in the source citation. I've made an initial attempt at citation that's compliant. It's probably overkill, but here goes:
Map showing ...... is a screenshot of of the OpenStreetMap website. OpenStreetMap ® is open data, licensed under the Open Data Commons Open Database License (ODbL) by the OpenStreetMap Foundation (OSMF). The cartography in OpenStreetMap ® map tiles, and our documentation, are licensed under the Creative Commons Attribution-ShareAlike 2.0 license (CC BY-SA). Further information is available from the OpenStreetMap copyright page.
In wiki markup this would be:
Map showing [https://www.openstreetmap.org/directions?engine=fossgis_osrm_bike&route=51.8133%2C-2.1529%3B50.7401%2C-3.0663#map=8/51.324/-2.593 route from Cranham, Gloucestershire to Colyton, Devon] is a screenshot of of the OpenStreetMap website. OpenStreetMap [https://www.openstreetmap.org/copyright#trademarks ®] is open data, licensed under the [https://opendatacommons.org/licenses/odbl/ Open Data Commons Open Database License] (ODbL) by the [https://osmfoundation.org/ OpenStreetMap Foundation] (OSMF). The cartography in OpenStreetMap ® map tiles, and our documentation, are licensed under the [https://creativecommons.org/licenses/by-sa/2.0/ Creative Commons Attribution-ShareAlike 2.0] license (CC BY-SA). Further information is available from the OpenStreetMap [https://www.openstreetmap.org/copyright copyright page].
To be on the safe side, and since I've cropped out the original one, it would be aptly cautious to include a copyright notice on the image itself. I've taken the liberty to upload the same map as an example on one of my free space profiles: https://www.wikitree.com/photo/png/JNM_G2G_Images-15