Is the input of `tf.image.resize_images` must have static shape?

Question

I run the code below, it raises an ValueError: \'images\' contains no shape. Therefore I have to add the line behind # to set the static shape, but

Answer 1

The issue here actually comes from the fact that tf.image.decode_image doesn't return the shape of the image. This was explained in these two GitHub issues: issue1, issue2.

The problem comes from the fact that tf.image.decode_image also handles .gif, which returns a 4D tensor, whereas .jpg and .png return 3D images. Therefore, the correct shape cannot be returned.

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The solution is to simply use tf.image.decode_jpeg or tf.image.decode_png (both work the same and can be used on .png and .jpg images).

def _decode_image(filename):
    image_string = tf.read_file(filename)
    image_decoded = tf.image.decode_jpeg(image_string, channels=3)
    image = tf.cast(image_decoded, tf.float32)
    image_resized = tf.image.resize_images(image, [224, 224])

    return image_resized