diff --git a/beets/util/artresizer.py b/beets/util/artresizer.py
index 0082b1220..d81902315 100644
--- a/beets/util/artresizer.py
+++ b/beets/util/artresizer.py
@@ -256,7 +256,8 @@ class IMBackend(LocalBackend):
             '-colorspace', 'gray', 'MIFF:-'
         ]
         compare_cmd = self.compare_cmd + [
-            '-define', 'phash:colorspaces=sRGB,HCLp', '-metric', 'PHASH', '-', 'null:',
+            '-define', 'phash:colorspaces=sRGB,HCLp',
+            '-metric', 'PHASH', '-', 'null:',
         ]
         log.debug('comparing images with pipeline {} | {}',
                   convert_cmd, compare_cmd)