How can I get a specific front matter array element in my template?

I have an array in my post’s front matter

images: ["1.jpg", "2.jpg", "3.jpg"]

From my templates I can range through this array without any problems:

{{ range $index, $image := .Params.images }}
    {{ $index }} {{ $range }}
{{ end }}

But what if I want to get the first element of this array? I tried with Index but it doesn’t work

{{ index .Params.images 0 }}
{{ index (index .Params "images") 0 }}

They give me this error:

executing "main" at <index .Params.images...>: error calling index: index of untyped nil

What am I doing wrong?

You can find a good example of a similar snippet in the internal twitter_cards.html template, or here (my tweaked version of that template as a partial).