diff --git a/cidre/src/cf/dictionary.rs b/cidre/src/cf/dictionary.rs
index 1b2396bf..3171b490 100644
--- a/cidre/src/cf/dictionary.rs
+++ b/cidre/src/cf/dictionary.rs
@@ -379,7 +379,10 @@ extern "C" {
 
 }
 
-define_cf_type!(DictionaryMut(Dictionary));
+define_cf_type!(
+    #[doc(alias = "CFMutableDictionary")]
+    DictionaryMut(Dictionary)
+);
 
 impl DictionaryMut {
     pub fn with_capacity(capacity: usize) -> arc::R<Self> {
@@ -482,6 +485,19 @@ where
     }
 }
 
+impl DictionaryOf<cf::String, cf::Plist> {
+    pub fn value<'a>(&'a self, key: &cf::String) -> Option<&'a cf::Plist> {
+        let mut result = None;
+        unsafe {
+            if CFDictionaryGetValueIfPresent(&self.0, key.as_type_ptr(), &mut result) {
+                Some(std::mem::transmute(result))
+            } else {
+                None
+            }
+        }
+    }
+}
+
 impl<K, V> std::ops::Deref for DictionaryOf<K, V>
 where
     K: arc::Retain,
diff --git a/cidre/src/cg/image/source.rs b/cidre/src/cg/image/source.rs
index ac71ea10..d7f8b2a6 100644
--- a/cidre/src/cg/image/source.rs
+++ b/cidre/src/cg/image/source.rs
@@ -60,7 +60,10 @@ impl Src {
 
     #[doc(alias = "CGImageSourceCopyProperties")]
     #[inline]
-    pub fn props(&self, options: Option<&cf::Dictionary>) -> Option<arc::R<cf::Dictionary>> {
+    pub fn props(
+        &self,
+        options: Option<&cf::Dictionary>,
+    ) -> Option<arc::R<cf::DictionaryOf<cf::String, cf::Plist>>> {
         unsafe { CGImageSourceCopyProperties(self, options) }
     }
 
@@ -70,7 +73,7 @@ impl Src {
         &self,
         index: usize,
         options: Option<&cf::Dictionary>,
-    ) -> Option<arc::R<cf::Dictionary>> {
+    ) -> Option<arc::R<cf::DictionaryOf<cf::String, cf::Plist>>> {
         unsafe { CGImageSourceCopyPropertiesAtIndex(self, index, options) }
     }
 
@@ -119,13 +122,13 @@ extern "C-unwind" {
     fn CGImageSourceCopyProperties(
         isrc: &Src,
         options: Option<&cf::Dictionary>,
-    ) -> Option<arc::R<cf::Dictionary>>;
+    ) -> Option<arc::R<cf::DictionaryOf<cf::String, cf::Plist>>>;
 
     fn CGImageSourceCopyPropertiesAtIndex(
         isrc: &Src,
         index: usize,
         options: Option<&cf::Dictionary>,
-    ) -> Option<arc::R<cf::Dictionary>>;
+    ) -> Option<arc::R<cf::DictionaryOf<cf::String, cf::Plist>>>;
 
     fn CGImageSourceCreateImageAtIndex(
         isrc: &Src,