When I try to use the following snippet of code to try to predict on a batch of images, I get a message saying that no image were found:

test_datagen = ImageDataGenerator()

test_generator = test_datagen.flow_from_directory(
        target_size=(300, 300),
        shuffle = False,

filenames = test_generator.filenames

My directory structure is as follows. I first have a main directory named dogs_vs_cats in which I have two sub directories train and test containing the respective images and also the notebook which contains this code.

  • $\begingroup$ Could you post the exact ErrorMessage? $\endgroup$
    – Danny
    May 9, 2019 at 14:40
  • $\begingroup$ I actually solved the issue just now. I forgot to create 2 subdirectories inside the respective train and test folders and put the images in them. Thanks anyway $\endgroup$ May 9, 2019 at 14:45
  • $\begingroup$ The output actually was 'Found 0 images belonging to 0 classes' $\endgroup$ May 9, 2019 at 14:47

3 Answers 3


Keras generator alway looks for subfolders (representing the classes). Images insight the subfolders are associated with a class.

So when you work on C:\images\ and you have two classes, say C1, C2, you need to create subfolders C:\images\C1\ and C:\images\C2\. The directory insight the generator function should point to C:\images\.

See this post for the case of image prediction: https://stackoverflow.com/a/55991598/9524424

  • 1
    $\begingroup$ Thanks a lot. This worked for me $\endgroup$ May 12, 2019 at 12:07

There is another option where you do not have to copy the test file into another test file:

datagen = ImageDataGenerator()

test_data = datagen.flow_from_directory('.', classes=['test'])

This solved my problem. For more info see this.


There could be two situations when you run ImageDataGenerator on test set of images.

Case #1: Test folder has subfolders representing the classes. Peter has answered this part.

Case #2: There are no labelled test images. In this case, you will have a single test folder which contains all the images that you want to classify.

Kyle Banks has written a tip to handle this in his blog: https://kylewbanks.com/blog/loading-unlabeled-images-with-imagedatagenerator-flowfromdirectory-keras


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