fix #2 for Keras blog post (#2420)

* blog post explaining how to load Llama 3.2 in Keras

* added table of contents entry

* merged tebale of contents

* additional visual assets

* renaming files to conform to standard

* finalized keras blog post + assets

* typo fixes

* a couple of edits to the blog post

* removed unused file

* fixed thumbnail

* fix #2 for keras post thumbnail

_blog.yml

@@ -4821,7 +4821,7 @@
 - local: keras-llama-32
  title: "Llama 3.2 in Keras"
  author: martin-gorner
- thumbnail: /blog/assets/keras-llama-32/thumbnail.gif
+ thumbnail: /blog/assets/keras-llama-32/thumbnail.jpg
  date: October 21, 2024
  tags:
  - keras