Batch Watermarking Images using Powershell

watermark.ps1

$watermark = "F:\filepath\watermark.png"
# This assumes composite.exe is part of PATH
$magick = "composite.exe -dissolve 15 -tile"
Get-ChildItem -Path 'F:\FilePath\*.png' -Recurse -Force |
Foreach-Object {
    $image = $_.FullName
    $cmdline = $magick + " `"" + $watermark + "`"" + " `"" + $_.FullName + "`"" + " `"" + $_.FullName + "`""
    Invoke-Expression -Command $cmdline
}