diff --git a/tests/pixelfed-garage.nix b/tests/pixelfed-garage.nix
index 2431ef8..096eab3 100644
--- a/tests/pixelfed-garage.nix
+++ b/tests/pixelfed-garage.nix
@@ -146,10 +146,7 @@ pkgs.nixosTest {
     with subtest("Image displays"):
       server.succeed(f"su - selenium -c 'selenium-script test@test.com {password}' >&2")
       server.copy_from_vm("/home/selenium/screenshot.png", "")
-      displayed_colors = subprocess.run(
-          ["magick", "screenshot.png", "-define", "histogram:unique-colors=true", "-format", "%c", "histogram:info:"],
-          capture_output=True
-      )
+      displayed_colors = server.succeed("magick /home/selenium/screenshot.png -define histogram:unique-colors=true -format %c histogram:info:")
       # check that the green image displayed somewhere
       green_check = re.match(".*#00FF00.*", displayed_colors.stdout.decode(), re.S)
       if green_check is None: