Show carousel should use small images :zap:

On the home page the Show carousel is seen very early on page load and so should be optimised. The first step would be to have images that are the correct size and also tell the browser their height and width. Modern browsers support other file formats and they can created pretty easily too. I have created a smaller show image and a WebP version of that too. In the future it would be great if their was a SVG version too, but that is hard with all the text in fancy fonts. BTW the Rocket is crying out to be a SVG that is defined once and referenced through out the page.

[slide.zip](https://github.com/JupiterBroadcasting/jupiterbroadcasting.com/files/9390229/slide.zip)

```diff --git a/themes/jb/layouts/index.html b/themes/jb/layouts/index.html
index 324911a..3e4464a 100644
--- a/themes/jb/layouts/index.html
+++ b/themes/jb/layouts/index.html
@@ -19,18 +19,38 @@

+ {{ $reImg := "^(.+)[.]([^.]+)$" }}
+ {{ $reSlide := "$1-slide.$2" }}
+ {{ $reWebP := "$1-slide.webp" }}

{{ range where .Site.Sections ".Title" "Shows" }}
{{ range .Pages }}
+ {{ $webpImg := print .Params.header_image | replaceRE $reImg $reWebP }}
+ {{ $webpFile := printf "%s" $webpImg | printf "%s%s" "static" }}
+ {{ $pngImg := print .Params.header_image | replaceRE $reImg $reSlide }}
+ {{ $pngFile := printf "%s" $pngImg | printf "%s%s" "static" }}

-
+
+ {{ if os.FileExists $webpFile }}
+
+ {{ end }}
+ {{ if os.FileExists $pngFile }}
+
+ {{ end }}
+
+

```