Demonstrates how to relink images using Sitecore PowerShell Extensions.

Relink Sitecore Image.ps1

$item = Get-Item -Path "master:\media library\images\koala"
$itemNew = Get-Item -Path "master:\media library\images\penguins"
$linkDb = [Sitecore.Globals]::LinkDatabase
$linkDb.GetReferrerCount($item) -gt 0
$links = $linkDb.GetReferrers($item)
foreach($link in $links) {
    $linkedItem = Get-Item -Path master:\ -ID $link.SourceItemID 
    $itemField = $linkedItem.Fields[$link.SourceFieldID]
    $field = [Sitecore.Data.Fields.FieldTypeManager]::GetField($itemField)
    
    $linkedItem.Editing.BeginEdit()
    $field.Relink($link, $itemNew)
    $linkedItem.Editing.EndEdit()
}

I think it would be super useful if we added a couple of commandlets, based on that brilliant bit of code
like Get-ItemReferrers & possibly Relink-Item. You did it again! I didn't think it would be either that succinct or even viable!

Also - great use case scenario!