How to Convert Images to App Icons for All Platforms

Publishing an app means submitting an icon that meets strict size and format requirements for each app store. iOS alone needs over a dozen icon sizes ranging from 20x20 to 1024x1024 pixels. Android requires adaptive icons in multiple densities. HarmonyOS has its own set of dimensions. Manually resizing an image for each of these is tedious and error-prone. An app icon converter solves this by taking a single source image and generating every required size instantly.

In this guide, we walk through the entire process of converting an image into production-ready app icons for all major platforms using IconForge, a free client-side tool that processes everything directly in your browser.

Why You Need Different Icon Sizes

Each operating system uses app icons in different contexts — the home screen, settings panel, notification bar, app store listing, and search results. To appear crisp on every screen density and in every context, you must provide icons at multiple resolutions. Here is what each platform expects:

• iOS — Apple requires icons in sizes ranging from 20x20 up to 1024x1024 pixels. These are bundled into anAppIcon.appiconset folder inside your Xcode project. Missing even one size can trigger a rejection during App Store review.
• Android — Google Play and the Android system expect adaptive icons at multiple density buckets: mdpi, hdpi, xhdpi, xxhdpi, and xxxhdpi. You also need a separate 512x512 icon for the Play Store listing.
• HarmonyOS— Huawei's platform requires icons in specific sizes for its app gallery, home screen, and system UI, with its own set of density variants.

Rather than opening an image editor for each size, an app icon converter handles the entire batch in one pass — saving time and ensuring pixel-perfect output.

Step-by-Step Guide to Converting Your Image

Follow these six steps to generate all the app icons you need in under a minute.

Supported Image Formats

IconForge supports the most common image formats, so you can start with whatever file you already have:

• PNG — The recommended format. Supports transparency and lossless quality. Ideal for icons with no background.
• JPG / JPEG — Widely used for photos. Works well for icons with solid or gradient backgrounds.
• WEBP — A modern format with excellent compression. Fully supported as an input format.
• SVG — Vector format that scales perfectly. The converter rasterizes SVGs to the exact pixel sizes required by each platform.

All output icons are generated as PNG files, which is the format required by iOS, Android, and HarmonyOS.

Privacy & Security

When you use IconForge, your images never leave your device. The entire conversion process runs inside your browser using the HTML5 Canvas API. There are no server uploads, no cloud processing, and no stored copies of your files.

• 100% client-side — All resizing and generation happens locally in your browser.
• No account required — Use the tool instantly without signing up or providing any personal information.
• No data retention — Since nothing is uploaded, there is nothing to store, share, or delete. Close the tab and everything is gone.

This makes IconForge safe for proprietary app icons, confidential brand assets, and any other sensitive imagery.

Tips for Best Results

Follow these guidelines to ensure your app icons look great at every size:

• Use a high-resolution source — Start with at least 1024x1024 pixels. Lower resolutions will appear blurry when scaled down and then displayed on high-density screens.
• Keep the design simple — App icons are often displayed at very small sizes (as small as 16x16 on some platforms). Avoid fine details, thin lines, and small text that will become illegible at small sizes.
• Use bold colors and high contrast— Vibrant colors and strong contrast help your icon stand out on crowded home screens and in app store search results.
• Design for the rounded square — Both iOS and Android mask icons into rounded squares. Keep important content away from the edges and corners to avoid clipping.
• Test on real devices — After generating your icons, install a build on a physical device to verify how the icon looks on the home screen, in settings, and in notifications.

Icon Size Reference by Platform

Need a quick reference? Here are the key icon sizes for each platform:

For a complete list of every required size with detailed specifications, see our App Icon Sizes Guide.