diff --git a/projects/tetrapod/index.md b/projects/tetrapod/index.md
index 21faeaa9588cddc552e85120d49405eca74bf308..32b68413d25dbc2248a3e1091e62fd9e85d5c5da 100644
--- a/projects/tetrapod/index.md
+++ b/projects/tetrapod/index.md
@@ -41,6 +41,6 @@ that are joined by a fifth, which binds them together:
 
 All in all we propose that these five aspects can be arranged in a tetrapodal structure
 
-<img alt="the tetrapod image for the five aspects of doing mathematics" src="tetrapod-arms.jpg"/>
+<img alt="the tetrapod image for the five aspects of doing mathematics" src="tetrapod-arms.pdf"/>
 
 Feel free to include this image into your paper via the [tikz sources provided here](tetrapod-arms.tex)