diff --git a/src/data/mnist.jl b/src/data/mnist.jl
index ba9960f9..c4cfc1b0 100644
--- a/src/data/mnist.jl
+++ b/src/data/mnist.jl
@@ -69,12 +69,33 @@ end
 
 getfeatures(io::IO, index::Integer) = vec(getimage(io, index))
 
+"""
+    images()
+    images(:test)
+
+Load the MNIST images.
+
+Each image is a 28×28 array of `Gray` colour values (see Colors.jl).
+
+Returns the 60,000 training images by default; pass `:test` to retreive the
+10,000 test images.
+"""
 function images(set = :train)
   io = IOBuffer(read(set == :train ? TRAINIMAGES : TESTIMAGES))
   _, N, nrows, ncols = imageheader(io)
   [rawimage(io) for _ in 1:N]
 end
 
+"""
+    labels()
+    labels(:test)
+
+Load the labels corresponding to each of the images returned from `images()`.
+Each label is a number from 0-9.
+
+Returns the 60,000 training labels by default; pass `:test` to retreive the
+10,000 test labels.
+"""
 function labels(set = :train)
   io = IOBuffer(read(set == :train ? TRAINLABELS : TESTLABELS))
   _, N = labelheader(io)