diff --git a/docs/content/showcase/datapipelinearchitect.md b/docs/content/showcase/datapipelinearchitect.md
index 7b96a6532..a74eb835e 100644
--- a/docs/content/showcase/datapipelinearchitect.md
+++ b/docs/content/showcase/datapipelinearchitect.md
@@ -7,7 +7,7 @@ tags:
 - tech
 - blog
 - website
-thumbnail: /img/datapipelinearchitect-tn.png
+thumbnail: /img/datapipelinearchitect-tn.jpg
 title: Data Pipeline Architect
 ---
 
diff --git a/docs/content/showcase/davidrallen.md b/docs/content/showcase/davidrallen.md
index a7a15826c..06e802fd5 100644
--- a/docs/content/showcase/davidrallen.md
+++ b/docs/content/showcase/davidrallen.md
@@ -9,7 +9,7 @@ tags:
 - personal
 - blog
 - tech
-thumbnail: /img/davidrallen-tn.jpg
+thumbnail: /img/davidrallen-tn.png
 title: David Allen
 ---
 
diff --git a/docs/content/showcase/leepenney.md b/docs/content/showcase/leepenney.md
index 2c4bc7689..db8bfb45b 100644
--- a/docs/content/showcase/leepenney.md
+++ b/docs/content/showcase/leepenney.md
@@ -8,7 +8,7 @@ sitelink: http://leepenney.com/
 tags:
 - personal
 - website
-thumbnail: /img/leepenney-tn.png
+thumbnail: /img/leepenney-tn.jpg
 title: Lee Penney
 ---
 
diff --git a/docs/content/showcase/rakutentech.md b/docs/content/showcase/rakutentech.md
index a04bc3ddc..b78b3e8b1 100644
--- a/docs/content/showcase/rakutentech.md
+++ b/docs/content/showcase/rakutentech.md
@@ -8,7 +8,7 @@ sitelink: http://techblog.rakuten.co.jp/
 tags:
 - company
 - blog
-thumbnail: /img/rakutentech-tn.jpg
+thumbnail: /img/rakutentech-tn.png
 title: Rakuten Tech Blog
 ---
 
diff --git a/docs/content/showcase/rick-cogley-info.md b/docs/content/showcase/rick-cogley-info.md
index cc5651734..997a45757 100644
--- a/docs/content/showcase/rick-cogley-info.md
+++ b/docs/content/showcase/rick-cogley-info.md
@@ -11,6 +11,6 @@ tags:
 - blog
 - rickcogley
 - japan
-thumbnail: /img/rick_cogley_info-tn.png
+thumbnail: /img/rick_cogley_info-tn.jpg
 title: rick.cogley.info
 ---
diff --git a/docs/content/showcase/webstudylist.md b/docs/content/showcase/webstudylist.md
index df6a9c796..9ac86801d 100644
--- a/docs/content/showcase/webstudylist.md
+++ b/docs/content/showcase/webstudylist.md
@@ -11,6 +11,6 @@ tags:
 - education
 - courses
 - resources
-thumbnail: /img/webstudylist-tn.jpg
+thumbnail: /img/webstudylist-tn.png
 title: Web Study List
 ---
diff --git a/docs/static/img/datapipelinearchitect-tn.jpg b/docs/static/img/datapipelinearchitect-tn.jpg
new file mode 100644
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diff --git a/docs/static/img/datapipelinearchitect-tn.png b/docs/static/img/datapipelinearchitect-tn.png
deleted file mode 100644
index 08e111031..000000000
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diff --git a/docs/static/img/davidrallen-tn.jpg b/docs/static/img/davidrallen-tn.jpg
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new file mode 100644
index 000000000..937147dee
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diff --git a/docs/static/img/javaunion-tn.png b/docs/static/img/javaunion-tn.png
index 9d4d8057d..49c432c81 100644
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diff --git a/docs/static/img/leepenney-tn.jpg b/docs/static/img/leepenney-tn.jpg
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diff --git a/docs/static/img/rakutentech-tn.jpg b/docs/static/img/rakutentech-tn.jpg
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