Overfitting results with Random Forest Regression
Where are you evaluating the performance of your algorithm?
Are you making a train test split and evaluating in the test split? It might be that you overfitted your train and you are just measuring the accuracy there.
If you have made correctly the train/test split and the evaluation it could be that the images that you are predicting do not have the same properties/configuration/topology than the with you are trainning