Here's a PowerShell script that uses the .NET framework to add a button as an overlay to an existing image:

powershell
# Load the System.Drawing assembly
Add-Type -AssemblyName System.Drawing

# Load the image
$image = [System.Drawing.Image]::FromFile("C:\path\to\image.jpg")

# Create a new bitmap with the same dimensions as the image
$bitmap = New-Object System.Drawing.Bitmap $image.Width, $image.Height

# Create a graphics object from the bitmap
$graphics = [System.Drawing.Graphics]::FromImage($bitmap)

# Draw the image onto the bitmap
$graphics.DrawImage($image, 0, 0)

# Create a button object
$button = New-Object System.Windows.Forms.Button
$button.Text = "Click me!"
$button.Width = 100
$button.Height = 30

# Set the button's location on the image
$buttonLocation = New-Object System.Drawing.Point(50, 50)
$button.Location = $buttonLocation

# Draw the button onto the bitmap
$button.DrawToBitmap($bitmap, $button.Bounds)

# Save the modified image
$bitmap.Save("C:\path\to\modified_image.jpg")

# Clean up
$image.Dispose()
$bitmap.Dispose()
$graphics.Dispose()
$button.Dispose()