Provide an example to just display an image from MNIST dataset

[scls19fr]

Maybe this repository should provide an example (or examples) to just display an image from MNIST dataset (display array as raster image in Julia)

julia> using MNIST
julia> features = trainfeatures(1)
julia> label = trainlabel(1)
julia> NROWS, NCOLS = 28, 28
julia> a = reshape(features, NROWS, NCOLS)

With PyPlot

using PyPlot
matshow(a)

With Gadfly

using Gadfly
spy(a)

Ideally grayscale plots should be used

With ImageView

using ImageView
imshow(a)

or reversing black and white

imshow(255-a)