diff --git a/biobb_dna/test/unitests/test_backbone/test_puckering.py b/biobb_dna/test/unitests/test_backbone/test_puckering.py
index bd5c0371..46739810 100644
--- a/biobb_dna/test/unitests/test_backbone/test_puckering.py
+++ b/biobb_dna/test/unitests/test_backbone/test_puckering.py
@@ -17,4 +17,4 @@ def test_puckering(self):
         assert fx.exe_success(returncode)
         if platform.system() == 'Darwin':
             assert fx.equal(self.paths['output_csv_path'], self.paths['ref_csv_output'])
-        assert fx.equal(self.paths['output_jpg_path'], self.paths['ref_jpg_output'])
+        assert fx.equal(self.paths['output_jpg_path'], self.paths['ref_jpg_output'], percent_tolerance=20)