Why most free PNG to ICO tools produce a broken file
Search for a "PNG to ICO" converter and most of what you'll find does one thing: it takes your .png file and changes the file extension to .ico. The bytes inside never change. This can look like it works — some lenient image viewers and even a few browsers will display the renamed file just fine — but the file itself is not a valid ICO. It has none of the internal structure the ICO format requires.
That gap shows up at the worst times: strict favicon validators flag it, some older browsers refuse to load it, and Windows icon caches can reject it or fall back to a generic blank icon. PhotoConvert's PNG to ICO converter and favicon generator avoids this entirely by building a genuine ICO file from scratch, byte by byte, so every ICO consumer accepts it.
What makes it a real ICO file
When you choose ICO as the output format, PhotoConvert doesn't touch the file extension — it encodes an actual ICO container. That means writing a real ICONDIR header (6 bytes identifying the file as an icon), an ICONDIRENTRY (16 bytes describing the image's dimensions and where its data lives in the file), and a BITMAPINFOHEADER (40 bytes describing the bitmap itself), followed by actual 32-bit-per-pixel pixel data with a proper alpha channel so transparency is preserved correctly. This is the same structure every valid .ico file on Windows, in browsers, and in favicon validators is built from.
The ICONDIRENTRY's width and height fields are single bytes, which can only address up to 256 pixels per side (0 is used to mean 256). PhotoConvert automatically scales your source image down to fit within 256×256 if it's larger, preserving its aspect ratio rather than forcing it square. That single resolution comfortably covers the sizes that matter in practice: 16×16 for the browser tab icon, 32×32 for the Windows taskbar and shortcut icon, and 48×48 for the Windows desktop icon.
Adding the favicon to your site
Once you've downloaded the converted file, rename it to favicon.ico and upload it to the root directory of your website (the same folder as your homepage). Then add this line inside your page's <head> section:
<link rel="icon" type="image/x-icon" href="/favicon.ico">
Most browsers will also automatically check for a /favicon.ico at your site's root even without the tag, but including it explicitly guarantees consistent behavior across browsers and makes the intent clear to anyone maintaining the site later.
How to create a favicon from PNG
- Drop your
.pngfile into the upload box above, or click to browse. A square source image gives the cleanest favicon. - Confirm ICO - Real favicon file is selected as the output format (it's pre-selected for you).
- Click Convert to generate a real ICO file entirely in your browser.
- Download the file and rename it to
favicon.ico. - Upload it to your website's root directory and add the
<link rel="icon">tag to your<head>.
Being upfront about limits: this tool generates one resolution per conversion, not an auto-generated multi-size bundle that packs 16px, 32px, and 48px into a single container the way some dedicated favicon-generator services do. For the vast majority of sites, one real ICO file at up to 256×256 covers every size browsers and Windows actually request. If your specific build tooling requires a multi-resolution .ico container with several embedded sizes, a dedicated multi-size favicon generator will better suit that need — but for a standard, valid, working favicon, this is all you need.
Don't forget the Apple touch icon
iOS home-screen icons don't use the ICO file at all — Safari on iPhone and iPad looks for a separate apple-touch-icon, which is a plain 180×180 PNG, not an ICO. It's requested independently of your favicon. You can create that file with PhotoConvert's PNG converter options by resizing your source image to 180×180 and exporting it as PNG, since it's a different format and size entirely from the ICO favicon.
Frequently asked questions
Is this a real ICO file, or just a renamed PNG?
It's a real ICO file. PhotoConvert builds an actual ICONDIR header, an ICONDIRENTRY, a BITMAPINFOHEADER, and genuine 32-bit-per-pixel image data with an alpha-respecting pixel layout — the same byte structure every valid ICO file uses. A renamed PNG has none of that structure, which is why it fails in strict ICO validators and some icon caches even though the file extension says .ico.
What size should my favicon be?
PhotoConvert supports up to 256×256 pixels, the largest size the ICO format's single-byte dimension fields can address. That comfortably covers the common sizes browsers and operating systems actually request: 16×16 for browser tabs, 32×32 for Windows taskbar and shortcut icons, and 48×48 for Windows desktop icons.
Do I need a square image?
A square source PNG is recommended for the cleanest result, since every favicon slot in browsers and operating systems is square. A non-square source still produces a valid ICO file, but some consumers may stretch or crop it to fit a square space.
How do I add the favicon to my website?
Rename the downloaded file to favicon.ico and place it in your website's root directory, then add <link rel="icon" type="image/x-icon" href="/favicon.ico"> inside your page's <head> section.