When reading a GIF image, it seems that all the image is the same color:

$ convert bob/io/image/data/grace_hopper.png test.gif
$ ./bin/python
>>> import bob.io.image, numpy
>>> image = bob.io.image.load("test.gif")
>>> numpy.all(image[0] == image[0][0][0])
True
>>> image2 = bob.io.image.load("bob/io/image/data/grace_hopper.png")
>>> numpy.all(image2[0] == image2[0][0][0])
False

I am using the GIF version which is coming with the conda, which is currently libgif.so.7.0.0. I have not checked other GIF versions.