http://samplesite.com/sample1/image1.jpg

try
{
    # Load WinSCP .NET assembly
    Add-Type -Path "WinSCPnet.dll"

    # Setup session options
    $sessionOptions = New-Object WinSCP.SessionOptions
    $sessionOptions.Protocol = [WinSCP.Protocol]::Sftp
    $sessionOptions.HostName = "example.com"
    $sessionOptions.UserName = "user"
    $sessionOptions.Password = "mypassword"
    $sessionOptions.SshHostKeyFingerprint = "ssh-rsa 2048 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx"

    $session = New-Object WinSCP.Session

    $remoteRoot = "/home/user"

    try
    {
        # Connect
        $session.Open($sessionOptions)

        foreach ($line in [System.IO.File]::ReadLines("list.txt"))
        {
            if ($line -Match "http://[a-z.]+(/(.*)/[a-z0-9.]+)$")
            {
                $remotePath = $matches[1]
                $remoteDir = $matches[2]
                $localDir = $remoteDir -Replace "/", ""

                if (!(Test-Path $localDir))
                {
                    Write-Host "Creating directory $localDir"
                    New-Item $localDir -Type directory | Out-Null
                }

                Write-Host "Downloading $remotePath"
                $session.GetFiles(($remoteRoot + $remotePath), ($localDir + "")).Check()
            }
            else
            {
                Write-Host "$line does not have expected URL format"
            }
        }
    }
    finally
    {
        # Disconnect, clean up
        $session.Dispose()
    }

    exit 0
}
catch [Exception]
{
    Write-Host $_.Exception.Message
    exit 1
}