update last md

Author: grizzlytheodore

src/Compute/Compute/help/New-AzGalleryImageDefinition.md

@@ -20,7 +20,7 @@ New-AzGalleryImageDefinition [-ResourceGroupName] <String> [-GalleryName] <Strin
  [-EndOfLifeDate <DateTime>] [-Eula <String>] [-HyperVGeneration <String>] [-MinimumMemory <Int32>]
  [-MinimumVCPU <Int32>] [-MaximumMemory <Int32>] [-MaximumVCPU <Int32>] [-PrivacyStatementUri <String>]
  [-PurchasePlanName <String>] [-PurchasePlanProduct <String>] [-PurchasePlanPublisher <String>]
- [-ReleaseNoteUri <String>] [-Tag <Hashtable>] [-Feature <GalleryImageFeature[]>]
+ [-ReleaseNoteUri <String>] [-Tag <Hashtable>] [-Feature <GalleryImageFeature[]>] [-Architecture <String>]
  [-DefaultProfile <IAzureContextContainer>] [-WhatIf] [-Confirm] [<CommonParameters>]
 ```
 
@@ -78,7 +78,7 @@ New-AzGalleryImageDefinition -ResourceGroupName $rgName -GalleryName $galleryNam
 
 Creates a gallery image definition to contain image versions for specialized windows images.
 
-### Example 4: Create an image definition for generalized windows images and set features. 
+### Example 4: Create an image definition for generalized windows images and set features.
 
 ```powershell
 $rgName = "myResourceGroup"
@@ -186,6 +186,21 @@ Creates a gallery image definition for linux generalized images and specify eith
 
 ## PARAMETERS
 
+### -Architecture
+CPU architecture supported by an OS disk. Possible values are "X64" and "Arm64".
+
+```yaml
+Type: System.String
+Parameter Sets: (All)
+Aliases:
+
+Required: False
+Position: Named
+Default value: None
+Accept pipeline input: True (ByPropertyName)
+Accept wildcard characters: False
+```
+
 ### -AsJob
 
 Run cmdlet in the background