Procon

Procon allows you to instantly create a full set of icons, simply drag and drop your App Store (1024x1024) icon into Procon and let it do the rest. You can choose to export resized icons as individual images, or choose to create a preformatted AppIcon.appiconset folder that you can export directly into your project directory.

Features:

• Single Click Icon Set Creation:
• With one click, generate an AppIcon.appiconset folder complete with all icon sizes for your selected platform and the accompanying Contents.json file already filled out. This allows for direct exporting of an icon set into a project directory. Sets can be created with images in PNG or JPEG formats.
• Selective Exporting:
• Choose specific icon sizes to export in PNG or JPEG format
• Live Preview:
• Resize your icons live to get a feel for how they look at different sizes without having to generate images