What is Master icon?
A single high-resolution square PNG — ideally 512 px or larger with transparent margins. One source of truth beats exporting every size by hand from a design tool.
App Icon Resizer
Create website and app icons from one image
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App Icon Resizer
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How to generate app icons
Upload a square PNG
Drop your master icon — it is processed locally, never uploaded.
Choose a preset
Pick favicon (16/32/48) or app (128–512) sizes, or generate both sets.
Download the ZIP
Save the ZIP of transparent PNG icons and drop them into your project.
Frequently asked questions
Which sizes are generated?
Favicon preset: 16, 32 and 48 px. App preset: 128, 192, 256 and 512 px. Every file is a PNG, resized with a contain fit onto a transparent square.
Does it produce .ico files?
No. The output is PNG only. Modern browsers and most app stores accept PNG icons directly; a separate ICO wrapper is not generated.
What if my image is not square?
It is letterboxed: the image is scaled to fit inside the square with transparent padding, so nothing is cropped or stretched.
How many files can the ZIP contain?
At most 50 files across the presets. Each icon set is bundled into one ZIP you download directly from your browser.
One source, every size
Here is what each format is for, and when converting one PNG into full icon sets is the right move.
What is Icon set?
Predictable, contain-fit PNGs at the exact sizes browsers, PWAs and stores request: crisp 16 px favicons through 512 px launch icons, all generated from the same master.
When you need it
Use it when shipping a website favicon set, a PWA manifest icon set, or store listing icons. It outputs PNG only — if a platform explicitly requires .ico or .icns, convert or wrap those files with a dedicated tool.