Powershell script I use to make all the images needed for IOS and Windows App development.

gistfile1.txt

# Create-Icons "C:\dropbox\projects\super8bitme\assets\super-8bit-me-art.png" "C:\temp" "windows"
Function Create-Icons
{
param($sourceFile, $targeLocation, $platform = "ios")


    #$targetFile = Join-Path -path "C:\Temp" -ChildPath iTunesArtwork.png
    #convert $sourceFile -resize 512x512 $targetFile
  if ($platform -eq "ios")
	{
		$sizes = @{ "512x512"="iTunesArtwork";
					"1024x1024"="iTunesArtwork@2x";
					"57x57"="Icon";
					"114x114"="Icon@2x";
					"72x72"="Icon-72";
					"144x144"="Icon-72@2x";
					"29x29"="Icon-Small";
					"58x58"="Icon-Small@2x";
					"50x50"="Icon-Small-50";
					"100x100"="Icon-Small-50@2x";
					}
	}
	else{
		$sizes = @{ "50x50"="StoreLogo";
					"150x150"="Logo";
					"30x30"="SmallLogo";
					"620x300"="SplashScreen";
					"310x150"="WideLogo";
					"24x24"="BadgeLogo";
					"846x468"="PromoImage846x468";
					"558x756"="PromoImage558x756";
					"414x468"="PromoImage414x468";
					"414x180"="PromoImage414x180";
					}
	}
				
    foreach($key in $sizes.Keys)
    {
        $size = $key
        $filename = $sizes[$key]

        $targetFile = (Join-Path -path "C:\Temp" -ChildPath $filename) + ".png"

        convert $sourceFile -resize $size $targetFile
		
		# http://www.imagemagick.org/Usage/crop/
		# helps with images that aren't square
		# resize canvas to expected size and fill in black for the background
		
		#convert $targetFile -background "black" -gravity center -extent $size $targetFile
		convert $targetFile -background "#109fda" -gravity center -extent $size $targetFile
    }

}

# example usage
# Create-Icons "C:\temp\largeImage.PNG" "C:\temp" "windows"