View an image encoded in a Base64 line from clipboard

base64img.ps1

Add-Type -AssemblyName System.Drawing

function Test-Base64 {
    param (
        [string]$base64
    )
    try {
        [Convert]::FromBase64String($base64)
        return $true
    } catch {
        return $false
    }
}

try {
    $base64 = Get-Clipboard
    # Clean up the base64 string
    $base64 = $base64 -replace '^data:image\/\w+;base64,', ''  # Remove data URL prefix
    $base64 = $base64 -replace '\s+', ''  # Remove all whitespace
    $base64 = $base64 -replace '[^a-zA-Z0-9+/=]', ''  # Keep only valid base64 chars
    $base64 = $base64.PadRight([math]::Ceiling($base64.Length / 4) * 4, '=')  # Pad the base64 string

    if (-not (Test-Base64 $base64)) {
        Write-Error "Invalid base64 string"
        exit
    }

    $imageBytes = [Convert]::FromBase64String($base64)
    $memoryStream = New-Object System.IO.MemoryStream($imageBytes, 0, $imageBytes.Length)
    $bitmap = [System.Drawing.Bitmap]::FromStream($memoryStream)

    # Create a GDI graphics object to display the image
    $graphics = [System.Drawing.Graphics]::FromImage($bitmap)
    $graphics.DrawImage($bitmap, 0, 0)

    # Display the image in a new window
    $form = New-Object System.Windows.Forms.Form
    $form.Text = "Base64 Image Viewer"
    $form.Width = $bitmap.Width
    $form.Height = $bitmap.Height
    $form.BackgroundImage = $bitmap
    $form.BackgroundImageLayout = 'None'
    $form.ShowDialog()
}
catch {
    Write-Error "Error: $_"
}
finally {
    if ($memoryStream) { $memoryStream.Dispose() }
    if ($bitmap) { $bitmap.Dispose() }
    if ($graphics) { $graphics.Dispose() }
}