From Toadwater Guide
PlantAid is a planting aid for folks with crappy monitors and crappy eyesight. The small black circles show when a square is fertilized and help to see when trees/flowers are planted. Crops replace the circles with largish letters that go away after a minute or so.
In order to use this image mod set, save each image as the image's title in your TW "Images" folder then restart your client: