diff --git a/README.md b/README.md
index 2ba4f66..5241466 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 <div align="center">
-<a href="https://e.coding.net/?utm_source=huiha&utm_medium=banner&utm_campaign=march2019"><img src="images/ad-coding.jpg" width="700"></a>
+<a href="https://e.coding.net/?utm_source=huiha&utm_medium=banner&utm_campaign=march2019"><img src="images/ad-coding.png" width="700"></a>
 <br>
 📘 Summary
 &nbsp&nbsp&nbsp | &nbsp&nbsp&nbsp
diff --git a/README_Details.md b/README_Details.md
index c7ba109..81e594a 100644
--- a/README_Details.md
+++ b/README_Details.md
@@ -1,5 +1,5 @@
 <div align="center">
-<a href="https://e.coding.net/?utm_source=huiha&utm_medium=banner&utm_campaign=march2019"><img src="images/ad-coding.jpg" width="700"></a>
+<a href="https://e.coding.net/?utm_source=huiha&utm_medium=banner&utm_campaign=march2019"><img src="images/ad-coding.png" width="700"></a>
 <br>
 <a href="https://github.com/huihut/interview">📘 Summary</a>
 &nbsp&nbsp&nbsp | &nbsp&nbsp&nbsp
diff --git a/images/ad-coding.jpg b/images/ad-coding.jpg
deleted file mode 100644
index e6ee238..0000000
Binary files a/images/ad-coding.jpg and /dev/null differ
diff --git a/images/ad-coding.png b/images/ad-coding.png
new file mode 100644
index 0000000..c689a3c
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