Convert a PNG to an ICO file
Drag the PNG into Images by Edmund, choose ICO from the format menu and press Export. You get a single .ico file with four sizes inside it, which is what a favicon is: not one image, but a container holding several so the browser can pick the right one. Start from a square PNG at least 256 px across.
macOS 15 or later. Apple silicon Mac. Version 1.1.0, out 11 October 2026. What’s new.
Free, with nothing to unlock and no account.
Make one right here
Drop a square PNG in and get a real .ico back, with 16, 32, 48 and 256 px inside it and each one drawn from your original rather than shrunk from the size above. It happens in this tab, on your own machine: nothing is uploaded, and no email address is asked for.
PNG to ICO, step by step
- Drag in a square PNGSquare matters, because every size inside an ICO is square. At least 256 px across, since the app renders each size down from your file and never invents pixels by scaling up.
- Choose ICOThere is no size to pick. The set of sizes is a property of the format rather than a choice, so choosing ICO is the whole instruction.
- Press ExportOne .ico comes out. Drop it at the root of your site as favicon.ico, or point at it from your HTML if you keep assets in a folder.
One source, four renders, and the app refuses to invent pixels
An icon file is the one case where a single output needs several renders, so the conversion branches before the resizing stage rather than after it. That means each size inside the .ico is produced from your original image at full detail, rather than from an already shrunken copy, which is what keeps the 16 px version legible instead of mushy. The same rule that governs everything else applies here too: a bitmap is never scaled up. If your source is smaller than the largest size the format holds, the app tells you rather than stretching it, because an icon ladder quietly built out of upscaled pixels looks fine in the file listing and terrible in a browser tab.
Why not just use a converter website?
Favicon generators are the busiest corner of the converter web, and most of them want your logo, your email address and a moment of your patience for an advert. The file they hand back is a container of scaled copies, which is fine until you look at the 16 px one.
Doing it locally also means you can iterate. Designers rarely get a favicon right first time, and the loop of tweak, export, look is a great deal shorter when it does not go through an upload.
Questions
What size PNG should I start from?
Square, and at least 256 px on a side. That covers every size inside the file with room to spare. Larger is fine and costs nothing; smaller means the app has to refuse the biggest rung rather than upscale your image into it.
Is an ICO the same as a favicon?
A favicon is the job; .ico is the traditional file for it. Modern browsers also accept a PNG or an SVG, but .ico remains the one that works everywhere, including in the older corners of Windows, which is why it is still worth generating.
Why does one file contain several sizes?
So the software displaying it can choose. A browser tab, a bookmark bar and a desktop shortcut all want different pixel dimensions, and picking from a set beats scaling one image down badly at the moment of display.
Can I make a Mac app icon instead?
Yes, choose ICNS rather than ICO. It is the same idea with a different ladder of sizes, and the app writes that container by hand because the version built into macOS silently drops two of the sizes it should contain.
Other things it does
There is a full list on the Images by Edmund product page, along with what else the app does.
Get Images by Edmund.
Free, and it does the other eight jobs too. Two ways to get it when it lands: the Mac App Store, or straight from here.
macOS 15 or later. Apple silicon Mac. Version 1.1.0, out 11 October 2026. What’s new.