Convert JPG to ICO: Make Favicons and Windows Icons

ICO is the format browsers and Windows use for icons. It bundles multiple image sizes into a single file — 16×16 for browser tabs, 32×32 for taskbars, up to 256×256 for app launchers. If you have a JPG logo and need a favicon, converting it to ICO is a two-minute job with the right tool.

Here are the fastest paths:

What Is an ICO File?

ICO is a container format developed by Microsoft. Unlike JPG or PNG, a single .ico file can store multiple resolutions simultaneously. When Windows shows your file in Explorer, it picks the size that fits — 16×16 for small icons, 256×256 for large previews. Browsers do the same with favicons: they pull the 16×16 or 32×32 layer depending on the device pixel ratio.

JPG does not support transparency. That matters for icons, where you often want the background to disappear against whatever color is behind the icon. If your JPG has a white background and you convert it directly to ICO, the white rectangle stays. For solid logos on solid backgrounds this is fine. For anything that needs a transparent background, start from PNG instead.

JPG to ICO via ImageMagick CLI

ImageMagick 7.1 (open-source, Apache 2.0 license) is the most flexible option. It creates a proper multi-size ICO in one command.

Install ImageMagick 7.1:

# macOS (Homebrew)
brew install imagemagick

# Ubuntu / Debian
sudo apt-get install imagemagick

# Windows (winget)
winget install ImageMagick.ImageMagick

Verify version:

magick --version
# Version: ImageMagick 7.1.x

Convert JPG to a single-size ICO:

magick logo.jpg -resize 32x32 favicon.ico

Create a multi-size ICO (recommended for favicons):

magick logo.jpg \
  \( -clone 0 -resize 16x16 \) \
  \( -clone 0 -resize 32x32 \) \
  \( -clone 0 -resize 48x48 \) \
  \( -clone 0 -resize 256x256 \) \
  -delete 0 favicon.ico

This embeds four sizes in the ICO container. Browsers and Windows pick the best-fit layer automatically.

Check what sizes are inside your ICO:

magick identify favicon.ico
# favicon.ico[0] ICO 16x16
# favicon.ico[1] ICO 32x32
# favicon.ico[2] ICO 48x48
# favicon.ico[3] ICO 256x256

If your source JPG is small (say, 64×64), do not upscale it — icons scaled up look blurry. Use the largest source JPG you have, then let ImageMagick resize down.

JPG to ICO on Windows

Windows does not have a built-in ICO exporter, but there are two workable paths.

Option 1: Paint + icon editor (no install)

1. Open your JPG in Paint.
2. Crop or resize it to a square (use Resize → Pixels, check Maintain aspect ratio).
3. Save as PNG (Paint → Save as → PNG).
4. Open the PNG in an online ICO converter or a free tool like IcoFX (trial license) to export as .ico.

Paint itself cannot save .ico files directly. The extra step through an icon editor is unavoidable unless you install ImageMagick.

Option 2: ImageMagick on Windows

Install via winget (shown above) and run the same magick commands. PowerShell and Command Prompt both work.

JPG to ICO on macOS

macOS Preview cannot export ICO directly, but sips (built into macOS) can resize images. The iconutil command creates .icns (macOS native) not .ico. For ICO specifically, use ImageMagick or Pixotter.

Using sips + ImageMagick:

# Resize first with sips (optional, if source is very large)
sips -z 256 256 logo.jpg --out logo-256.jpg

# Convert to ICO with ImageMagick
magick logo-256.jpg -resize 32x32 favicon.ico

Using only sips (produces PNG, not ICO):

sips -s format png logo.jpg --out logo.png

Sips produces PNG output, not ICO. You still need ImageMagick or Pixotter to get to .ico. The sips step is only useful if you want to pre-process the image size before conversion.

Why Start with PNG Instead of JPG

JPG uses lossy compression and does not support transparency. When you convert JPG → ICO, you get a flat icon with whatever background color was in the original photo.

PNG supports a full alpha channel. If your icon has a transparent background in PNG form, that transparency carries through to the ICO file. This matters when:

• The icon appears on dark and light backgrounds
• You're using the ICO as a Windows application icon (transparent icons blend into the taskbar)
• The favicon sits on pages with different background colors

The recommended workflow when transparency matters:

1. Start from the original vector or high-resolution source.
2. Export as PNG with a transparent background.
3. Convert PNG → ICO using ImageMagick or Pixotter.

If you only have a JPG, you can remove the background first — Pixotter's background removal tool can help — then convert the resulting PNG to ICO.

For more on when each format applies, see JPG vs PNG: Which Format Should You Use?

You can also follow the companion guide Convert PNG to ICO which covers the full transparent-background workflow.

ICO Size Requirements

Different contexts need different ICO sizes. Here is what to include:

For favicon implementation — including the <link> tag syntax and which sizes browsers actually use — see Favicon Size Guide: Every Size You Need.

A minimal favicon ICO (16×16 + 32×32) covers most web use cases. Add 48×48 if the ICO is also used as a Windows application icon. The full four-size ICO (16, 32, 48, 256) is the safe choice if the file will be used in both web and desktop contexts.

You can generate correctly-sized source images using Pixotter's resize tool before running the ICO conversion.

FAQ

Can I convert JPG to ICO without installing software?

Yes. Use Pixotter's converter — it runs in your browser, no install needed. Upload your JPG, select ICO as the output format, and download.

Does a JPG to ICO conversion support transparency?

No. JPG does not have an alpha channel, so there is no transparency to carry into the ICO. If you need a transparent icon, convert the JPG to PNG first (remove the background), then convert PNG to ICO.

What size should my source JPG be before converting?

Use the largest version you have, ideally 256×256 pixels or larger. ICO conversion scales down, which always looks better than scaling up. A 64×64 source upscaled to 256×256 will look blurry.

Why does my favicon still show the old icon after replacing it?

Browsers aggressively cache favicons. Force-refresh with Ctrl+Shift+R (Windows/Linux) or Cmd+Shift+R (macOS), or open DevTools → Application → Clear Storage and reload.

Can I use ImageMagick on Windows without admin rights?

Yes. The portable version of ImageMagick 7.1 runs without installation. Download the portable ZIP from imagemagick.org, extract it, and run magick.exe directly from the extracted folder.

What's the difference between ICO and ICNS?

ICO is the Windows and web standard (used for favicons and Windows app icons). ICNS is the macOS native format (used for Mac app icons). If you're building a cross-platform app, you need both. For web favicons, ICO is the right choice — all browsers support it.

ICO conversion is simpler than it looks once you know the format. For a quick one-off, Pixotter's converter handles it in your browser. For repeatable multi-size ICO generation in a build pipeline, ImageMagick 7.1's one-liner is the right tool.

If your icon needs a transparent background, follow the PNG to ICO workflow instead — it's the same process with one extra step at the start. And once you have your ICO file, the Favicon Size Guide covers exactly how to wire it into your HTML and what each browser does with it.

For the full picture on making a favicon from scratch — choosing the right source image, sizing it, and handling all the browser edge cases — see How to Make a Favicon.