diff --git a/Gemfile.lock b/Gemfile.lock
index bc1daeeac..007e02140 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -165,7 +165,7 @@ GEM
     chartkick (3.4.0)
     childprocess (3.0.0)
     choice (0.2.0)
-    chunky_png (1.3.11)
+    chunky_png (1.4.0)
     clamav-client (3.2.0)
     coderay (1.1.3)
     coercible (1.0.0)
diff --git a/app/controllers/new_administrateur/attestation_templates_controller.rb b/app/controllers/new_administrateur/attestation_templates_controller.rb
index 00d5ea86b..68a06e3a8 100644
--- a/app/controllers/new_administrateur/attestation_templates_controller.rb
+++ b/app/controllers/new_administrateur/attestation_templates_controller.rb
@@ -60,7 +60,7 @@ module NewAdministrateur
 
     def uninterlaced_png(uploaded_file)
       if uploaded_file&.content_type == 'image/png'
-        chunky_img = ChunkyPNG::Image.from_io(uploaded_file)
+        chunky_img = ChunkyPNG::Image.from_io(uploaded_file.to_io)
         chunky_img.save(uploaded_file.tempfile.to_path, interlace: false)
         uploaded_file.tempfile.reopen(uploaded_file.tempfile.to_path, 'rb')
       end