diff --git a/reference/image/functions/imagegd.xml b/reference/image/functions/imagegd.xml
index 82a004605a..eefaf8d1fb 100644
--- a/reference/image/functions/imagegd.xml
+++ b/reference/image/functions/imagegd.xml
@@ -10,7 +10,7 @@
   <methodsynopsis>
    <type>bool</type><methodname>imagegd</methodname>
    <methodparam><type>resource</type><parameter>image</parameter></methodparam>
-   <methodparam choice="opt"><type>mixed</type><parameter>to</parameter></methodparam>
+   <methodparam choice="opt"><type>mixed</type><parameter>to</parameter><initializer>NULL</initializer></methodparam>
   </methodsynopsis>
   <para>
    Outputs a GD image to the given <parameter>to</parameter>.
diff --git a/reference/image/functions/imagegd2.xml b/reference/image/functions/imagegd2.xml
index faadfe7df6..03e01880d4 100644
--- a/reference/image/functions/imagegd2.xml
+++ b/reference/image/functions/imagegd2.xml
@@ -10,8 +10,8 @@
   <methodsynopsis>
    <type>bool</type><methodname>imagegd2</methodname>
    <methodparam><type>resource</type><parameter>image</parameter></methodparam>
-   <methodparam choice="opt"><type>mixed</type><parameter>to</parameter></methodparam>
-   <methodparam choice="opt"><type>int</type><parameter>chunk_size</parameter></methodparam>
+   <methodparam choice="opt"><type>mixed</type><parameter>to</parameter><initializer>NULL</initializer></methodparam>
+   <methodparam choice="opt"><type>int</type><parameter>chunk_size</parameter><initializer>128</initializer></methodparam>
    <methodparam choice="opt"><type>int</type><parameter>type</parameter><initializer>IMG_GD2_RAW</initializer></methodparam>
   </methodsynopsis>
   <para>