This will make future diffs easier to read because code changes modify the
hash/link, but the image data stays the same.
Note that there are whitespace diffs in the generated files where there
is no image. This is because there was a stray tab in the template before,
and now it's replaced by spaces.
Fixes#235
The current example shows `json.Unmarshal` on an array of bytes, including
`num:6.0`. In the output however this comes out as `6`. Even in the casting to
`float64`, it comes out as `6`. This can be confusion because it looks like a
simple `int`. By adding an arbitray `.13` you see it's a
float.
