$stream = New-Object System.IO.MemoryStream
$picturebox.Image.Save($stream, [System.Drawing.Imaging.ImageFormat]::Jpeg) | Out-Null
[byte[]]$pictureData = $stream.ToArray()
$stream.Dispose()
Set-ADUser -Identity testUser -Replace @{ thumbnailPhoto = $pictureData; jpegPhoto = $pictureData }