App icon set
Generate a full iOS/Android app icon size set from one square image, on your device.
Runs on your device. The file is never uploaded.
App icon set resizes one image into 16 lossless PNGs, the iOS sizes from 20 to 1024 and the Android sizes from 36 to 512. Each file is named after its platform label and pixel size. There are no options, and a non-square source is centre-cropped first. The 16 files arrive as separate downloads, never bundled into an archive.
Questions
Which sizes does it generate?
Sixteen PNGs from one image: iOS at 20, 29, 40, 60, 76, 120, 152, 180 and 1024 pixels, and Android at 36, 48, 72, 96, 144, 192 and 512 pixels. This is a curated list of the common launcher and store sizes rather than every size either platform has ever defined. There are no options at all; you drop an image and get the set.
Does my source image have to be square?
It is easier if it is, but not required. A non-square image is centre-cropped to a square first, using the shorter side, and the summary line says so: "(centre-cropped to square first)". Anything outside that centre square is lost, so if your logo sits off to one side, crop it yourself with Crop image before running this.
What are the files called?
Your base name, then -icon-, then the platform label and the pixel size, such as logo-icon-ios-180-180.png and logo-icon-android-512-512.png. Every file is a lossless PNG, whatever you dropped in. They arrive as sixteen separate downloads listed on the page, not as a ZIP archive, so you can take only the sizes your project needs and ignore the rest.
Do I get an .ico or an Xcode asset catalog?
No. The output is plain PNG files only. There is no .ico, no .icns, no Contents.json for an Xcode AppIcon set and no Android mipmap folder structure. It also does not add rounded corners, padding or a mask; platforms apply their own shape, and you can round corners yourself with Rounded corners if you need to.
Does it upload my logo?
No. The image is decoded once and resized sixteen times in a Web Worker on your device using the jSquash codecs, with a progress update per size. Nothing is uploaded and there is no account. Only JPG, PNG and WebP inputs are read; anything else stops with "only JPG, PNG and WebP are supported".