diff --git a/icnsutil/IcnsType.py b/icnsutil/IcnsType.py
index e37104e..3998f54 100644
--- a/icnsutil/IcnsType.py
+++ b/icnsutil/IcnsType.py
@@ -141,7 +141,7 @@ _TYPES = {x.key: x for x in (
     # Write support for these:
     Media('icp4', ['png', 'jp2', 'rgb'], 16, os=10.7),
     Media('icp5', ['png', 'jp2', 'rgb'], 32, os=10.7),
-    Media('icp6', ['png'], 64, os=10.7),
+    Media('icp6', ['png', 'jp2'], 48, os=10.7),
     Media('ic07', ['png', 'jp2'], 128, os=10.7),
     Media('ic08', ['png', 'jp2'], 256, os=10.5),
     Media('ic09', ['png', 'jp2'], 512, os=10.5),
diff --git a/tests/format-support-icns.zip b/tests/format-support-icns.zip
index 3724087..24e3004 100644
Binary files a/tests/format-support-icns.zip and b/tests/format-support-icns.zip differ
diff --git a/tests/format-support.py b/tests/format-support.py
index b825612..e726dd9 100644
--- a/tests/format-support.py
+++ b/tests/format-support.py
@@ -21,8 +21,8 @@ INFO = {
     24: ['sb24'],
     32: ['il32', 'icp5', 'ic11', 'ic05'],
     36: ['icsB'],
-    48: ['ih32', 'SB24'],
-    64: ['icp6', 'ic12'],
+    48: ['ih32', 'icp6', 'SB24'],
+    64: ['ic12'],
     128: ['it32', 'ic07'],
     256: ['ic08', 'ic13'],
     512: ['ic09', 'ic14'],
diff --git a/tests/test_icnsutil.py b/tests/test_icnsutil.py
index 57e64f8..818a5a7 100644
--- a/tests/test_icnsutil.py
+++ b/tests/test_icnsutil.py
@@ -270,7 +270,7 @@ class TestIcnsType(unittest.TestCase):
             ('it32', 'rgb', '', (128, 128), 49152),  # 3x8-bit
             ('t8mk', 'bin', 'mask', (128, 128), 16384),  # 8-bit mask
             ('ic05', 'argb', '', (32, 32), 4096),  # 4x8-bit
-            ('icp6', 'png', '', (64, 64), None),
+            ('icp6', 'png', '', (48, 48), None),
             ('ic14', 'png', '@2x', (512, 512), None),
             ('info', 'plist', '', None, None),
             ('sbtp', 'icns', 'template', None, None),