By following the steps below you will get proper preview images.
The map has an internal error with decals that does not effect game play.
Download each of these files(3) and replace the ones in the map folder using the new images.
Then change the line in the Battle Isles TeamPlay_AI_scenario file
preview = '/maps/Battle Isles TeamPlay_AI/Battle Isles TeamPlay_AI.jpg',
to read
preview = "",
You can also go to C:\ProgramData\FAForever\cache
find battle isles teamplay_ai.png and delete it ...then replace it with the downloaded file ....battle isles teamplay_ai
battle isles teamplay_ai.large
http://i.imgur.com/eXltnal.png
battle isles teamplay_ai
http://i.imgur.com/sQe4XkY.png
battle isles teamplay_ai.small
http://i.imgur.com/fMRhaSZ.png
If there are any map makers that can Edit the decals in this map please let us know how you achieved this feat.