[mod] thumbnail

Author: NaokiHori

README.rst

@@ -10,13 +10,10 @@ Simple IBM Solver
 .. |LastCommit| image:: https://img.shields.io/github/last-commit/NaokiHori/SimpleIBMSolver/main
 .. _LastCommit: https://github.com/NaokiHori/SimpleIBMSolver/commits/main
 
-.. image:: https://github.com/NaokiHori/SimpleIBMSolver/blob/main/docs/source/thumbnail.gif
+.. image:: https://github.com/NaokiHori/SimpleIBMSolver/blob/main/docs/source/snapshot2d.png
    :target: https://youtu.be/nMAyrIYET10
    :width: 100%
 
-.. image:: https://github.com/NaokiHori/SimpleIBMSolver/blob/main/docs/source/snapshot3d.png
-   :width: 50%
-
 ********
 Overview
 ********

docs/source/conf.py

@@ -5,7 +5,7 @@
 
 project = "Simple IBM Solver"
 author = "Naoki Hori"
-copyright = f"2019-2023, {author}"
+copyright = f"2019, {author}"
 
 extensions = [
         "sphinx.ext.mathjax",