How to update Item's Media Properties using SPE (Sitecore Powershell Extensions)

Question

I have an Image Field in an Item. When the image is uploaded to Media Library, the Alt field is not updated and hence when we look at the Image properties from Item, it is Blank. So far so good.

The content Author now has updated the Image's Alt Text and i can see that the "Default Alternate Text" is showing correctly as in screenshot below. But the content author is expecting the "Alternate Text" to be filled up with "Default Alternate Text".

I planned to fill it with SPE. When i tried to browse the "Alternate Text" field from SPE, it shows an xml with MediaID without Alt tag.

$Item["Article Thumbnail"]

$Item.PSFields."Article Thumbnail"

For both, I see an xml as

Now the question is how to fill "Alternate Text" from "Default Alternate Text". I can't access both fields from SPE. Any suggestions or solutions for this.

Answer 1

What you are trying to do is to update the raw value of the Image field.

To do this you need to get the target Image item from the raw value of the Image field and then get the Alternate Text of that image item. And then update the main item raw value to add alt text.

Sharing with you a sample script will help you to do this.

# Get the content Item by passing your item ID.
$item =  Get-Item -Path "master:" -Uri "sitecore://master/<your-item-id>" 

# Get the image field by passing your field name.
$imageField = [Sitecore.Data.Fields.ImageField]$item.Fields["<your-field-name>"]

# Get the actual Sitecore Image item by passing the mediaID (see your raw value)
$imageItem = Get-Item -Path master: -ID $imageField.mediaID

# Get the Alt value from the Image Item
$altValue = $imageItem.Fields["Alt"].Value

# Update the Main value 
$item.Editing.BeginEdit()
$item.Fields["Image"].Value = [string]::Format("<image mediaid='{0}' alt='{1}' />",$imageField.mediaID, $altValue)
$item.Editing.EndEdit()  

Now your raw value will look like this.

<image mediaid='{094AED03-02E7-4868-80CB-19926661FB77}' alt='Default Text' />

And you will be able to see it filled in your Image Properties. Hope this help.

Answer 2

By using below code you can replace Default Alternate Text field value with Alternate Text field value under specific media items node.

$mediaTemplateName = "Image"
$mediaParentFolderPath = "master:/sitecore/media library/MediaFolder"
$counter = 1

$allMediaItems = Get-ChildItem -Path $mediaTemplateName -Recurse
$filteredMediaItems = $allMediaItems | Where-Object { $_.Fields["Alt"].Value -eq "" -and [Sitecore.Data.Managers.TemplateManager]::GetTemplate($_).InheritsFrom("Image") }

foreach($MediaItem in $filteredMediaItems) {
       
      $defaultAltValue = $MediaItem.Fields["Default Alternate Text"].Value
        #Update Alt tag

        $MediaItem.Editing.BeginEdit()
        $MediaItem.Fields["Alt"].Value = $defaultAltValue
        $MediaItem.Editing.EndEdit()

        Write-Host $counter " -> " $altValue " -> " $MediaItem.ItemPath
        $counter = $counter + 1
}