Compress-Png.ps1

function Compress-Png {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, Position = 0, ValueFromPipeline)]
        [string]$InputFile,

        [Parameter(Mandatory, Position = 1)]
        [string]$OutFile
    )
    
    begin {
        $ProcessInfo = New-Object -TypeName System.Diagnostics.ProcessStartInfo
        $ProcessInfo.CreateNoWindow = $true
        $ProcessInfo.FileName = 'pngquant.exe'
        $ProcessInfo.Arguments = '--quality=65-80 --skip-if-larger -'
        $ProcessInfo.UseShellExecute = $false
        $ProcessInfo.RedirectStandardInput = $true
        $ProcessInfo.RedirectStandardOutput = $true
    }
    
    process {
        $InputFile = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($InputFile.Trim())
        $OutFile = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($OutFile.Trim().TrimEnd([IO.Path]::DirectorySeparatorChar))
        if (-not (Test-Path -LiteralPath $InputFile -PathType Leaf)) {
            Write-Error -Exception ([System.IO.FileNotFoundException]::('The input file is not exist.'))
            return
        }

        $OutputDirectory = Split-Path -Path $OutFile -Parent
        if (-not (Test-Path -LiteralPath $OutputDirectory -PathType Container)) {
            $null = New-Item -Path $OutputDirectory -ItemType Directory
        }

        try {
            $Process = [System.Diagnostics.Process]::Start($ProcessInfo)
            $InputFileStream = [System.IO.File]::Open($InputFile, [System.IO.FileMode]::Open)
            $InputFileStream.CopyTo($Process.StandardInput.BaseStream)
            $InputFileStream.Close()
            $Process.StandardInput.BaseStream.Flush()

            $OutputFileStream = [System.IO.FileStream]::new($OutFile, [System.IO.FileMode]::Create, [System.IO.FileAccess]::Write)
            $Process.StandardOutput.BaseStream.CopyTo($OutputFileStream)
        }
        catch {
            Write-Error -Exception $_.Exception
        }
        finally {
            if ($null -ne $InputFileStream) {
                $InputFileStream.Close()
                $InputFileStream.Dispose()
            }
            if ($null -ne $OutputFileStream) {
                $OutputFileStream.Close()
                $OutputFileStream.Dispose()
            }
        }
    }
    
    end {
        
    }
}