diff --git a/skimage/data/__init__.py b/skimage/data/__init__.py
index ac55557f..2dc9fa78 100644
--- a/skimage/data/__init__.py
+++ b/skimage/data/__init__.py
@@ -155,7 +155,7 @@ def immunohistochemistry():
     No known copyright restrictions.
 
     """
-    return load("ihc.jpg")
+    return load("ihc.png")
 
 
 def chelsea():
@@ -169,4 +169,4 @@ def chelsea():
     No copyright restrictions.  CC0 by the photographer (Stefan van der Walt).
 
     """
-    return load("chelsea.jpg")
+    return load("chelsea.png")