Pcolormesh like replacement using Images.jl?

[robblackwell]

Values must be between 0 and 1, so this works:

using Images

function matrix_to_gray(a::Matrix)
    a = Float64.(a)
    b = minimum(a)
    c = maximum(a)
    d = (a .- b) / (c -b)
    colorview(Gray, d)
end