When ICO Converter turns PNG into ICO
Make a favicon or a Windows icon from a square logo.
What ICO Converter changes in the picture
The image is resized and saved as an ICO.
Start with a simple, square picture. A wide photo makes a bad icon.
Why ICO Converter is its own job
ICO Converter sits on this site because PNG and ICO are not interchangeable, even when they look similar in a file list. Make a favicon or a Windows icon from a square logo. Use PNG when a logo must stay crisp or when the background must stay transparent. A site favicon or an old desktop shortcut is the usual reason to make an ICO.
The image is resized and saved as an ICO.
The PNG file you already have
PNG keeps sharp edges and transparency. Screenshots, logos, and diagrams belong in PNG. Photographs are usually much larger as PNG than as JPG, with little visual gain.
Keep the PNG master of a logo. Export JPG only for the places that refuse PNG.
What a ICO result is for
The download has to be ICO, because that is the format the next step named. A site favicon or an old desktop shortcut is the usual reason to make an ICO. The icon export here is a small image, typically 256 pixels, not a full design suite.
Start from a simple, high-contrast mark. Do not expect a multi-resolution icon editor.
How to tell that ICO Converter worked
ICO Converter is worth using only when ICO is what the next step actually named. Make a favicon or a Windows icon from a square logo. What you get from ICO Converter: The image is resized and saved as an ICO. Before you trust it: Start with a simple, square picture. A wide photo makes a bad icon. The file stays in your browser and is not uploaded. The limit is 100 MB. Keep the original until the download has been opened in the program that will use it. A second pass rarely helps. If the first ICO file is rejected, read the error from the program that rejected it. Another conversion of a bad result usually makes the file worse, not more compatible. When you are done, you should still have the PNG original and one ICO download that you have opened. If those two are the same kind of failure, this was the wrong tool and the page above is the place that says so. Photos fail uploads for three separate reasons: the format name, the pixel size, and the kilobyte size. ICO Converter only does the PNG to ICO step. If the form also prints a pixel size or a 20 KB or 50 KB cap, do that step with the matching tool, starting from the original each time. A second lossy save will not recover detail.
Here is the decision for ICO Converter. You start with PNG and you stop when a real program accepts ICO. Text in a screenshot stays sharper than it does in a heavy JPG. A photo squeezed into an icon becomes a tiny, muddy picture. If those two sentences describe a tradeoff you do not want, do not convert. Renaming the extension by hand will not do this job. Running the tool twice on its own output will not do it either.
Start with a simple, square picture. A wide photo makes a bad icon.
A related step, if you still need one, is JPG to PNG.
Other jobs start from the homepage, where each tool is named for the conversion it actually does.