It is awesome that you can use the .NET framework in Powershell. I am working on a website that contains a gallery. I got a lot of pictures sent in different sizes. At the moment I am only interested in pictures in a certain size. I used Powershell to find pictures in a folder with a specified height. Take a look.
[System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")
foreach ($file in get-childitem c:\web\photos -Filter "*.jpg" | where {[System.Drawing.Image]::FromFile($_.fullname).Height -eq 425 })
{
cp c:\web\photos\$file c:\web\photos\chosen\$file
}

