JPEG to ICO converter

JPG to ICO can wrap a JPEG preview into an icon container, but it does not invent transparency or build a full favicon size ladder.

Converted with Image engine · nothing stored
Free: 5 conversions a day · 5 MB each
Higher limits →

From real runs

What you get — and what changes

Element	Result	What happens
Large input handling	Changed	The 640×480 JPG was thumbnailed to a 256×192 ICO entry, proving inputs larger than 256 pixels are reduced.
Icon size set	Lost	The 41,177 byte ICO contained one 256×192 image, not separate 16, 32, 48, and 256 pixel renditions.
Transparency	Lost	The output opened as RGB because the JPEG source had no alpha channel to pass into the ICO.
Aspect ratio	Kept	The 4:3 photo ratio stayed 4:3 inside the icon entry, which is usually wrong for square favicon slots.
JPEG artifacts	Kept	Compression artifacts already present in the source photo remained visible after the icon was packaged.
Camera metadata	Lost	The ICO container did not retain JFIF or camera-style metadata from the source image inspection.

Large input handling Changed
The 640×480 JPG was thumbnailed to a 256×192 ICO entry, proving inputs larger than 256 pixels are reduced.
Icon size set Lost
The 41,177 byte ICO contained one 256×192 image, not separate 16, 32, 48, and 256 pixel renditions.
Transparency Lost
The output opened as RGB because the JPEG source had no alpha channel to pass into the ICO.
Aspect ratio Kept
The 4:3 photo ratio stayed 4:3 inside the icon entry, which is usually wrong for square favicon slots.
JPEG artifacts Kept
Compression artifacts already present in the source photo remained visible after the icon was packaged.
Camera metadata Lost
The ICO container did not retain JFIF or camera-style metadata from the source image inspection.

Sample conversions

Photo-like JPEG source

Input: 13,991 byte JPG at 640×480 with a gradient background and a drawn label.
Output: 41,177 byte ICO containing one RGB image at 256×192. It was larger than the JPG and not square.

Portrait photo used as favicon art

Input: A rectangular JPEG crop selected because no logo source was available.
Output: An opaque icon entry that fit within 256 pixels. Browser-tab use would need square cropping and hand checking at small sizes.

A real JPEG → ICO run

We converted our JPEG sample (42 KB) with Image engine on 2026-10-20. It took 33 ms and produced a 13 KB ICO file, 70% smaller than the input. The engine raised 1 warning, listed below.

Input · sample.jpg · 42 KB

1200 × 800 px, baseline

Width: 1,200
Height: 800
Encoding: baseline

Output · sample.ico · 13 KB

256 × 171 px, 1 size: 256×171

Width: 256
Height: 171
Encoding: 1 size: 256×171

Image metadata stripped from output.

Options and when to change them

width: Set width to pre-shape the JPEG before the ICO writer applies its 256 pixel thumbnail limit.
height: Set with width to make a square canvas; otherwise a rectangular photo can remain rectangular inside ICO.
fit: Use cover when cropping the photo to a square is better than padded or non-square icon output.

Do it yourself

ImageMagick 7

bash

magick source.jpg -resize 256x256^ -gravity center -extent 256x256 -define icon:auto-resize=256,48,32,16 favicon.ico

This is better for favicons than the current API result because it crops square and writes multiple icon sizes.

JPEG to ICO by API or MCP

The HTTP API and the MCP server run the exact engine this page uses (Image engine); the response carries the same warnings the web converter shows. Check support first with GET /api/v1/pairs?from=jpg&to=ico.

curl

curl -X POST https://filetypeconverters.com/api/v1/convert \
  -H "Authorization: Bearer $FTC_API_KEY" \
  -F "file=@input.jpg" -F "from=jpg" -F "to=ico" \
  -F 'options={"dpi":96}' \
  --output output.ico

Options this engine accepts for JPEG → ICO

Key	Applies to	Type	Default
dpi	Reading JPEG	number	96
width	Writing ICO	number	0
height	Writing ICO	number	0
fit	Writing ICO	contain · cover · fill	contain
quality	Writing ICO	number	90
background	Writing ICO	string	#ffffff
stripMetadata	Writing ICO	boolean	true

API reference

When this is the wrong conversion

Use /convert/png-to-ico when you have transparent square logo art instead of a photo.
Use /convert/jpg-to-png before manual editing if you need to cut out a transparent icon shape.
Do not use a detailed photo as a favicon unless it remains recognizable at 16 pixels.

JPEG to ICO questions

Does JPG to ICO make 16×16 and 32×32 images?

No in our run. The ICO contained a single 256×192 entry, so legacy favicon consumers would not get tuned small sizes.

Why is my JPG icon not transparent?

JPEG has no alpha channel. The ICO therefore starts opaque unless you remove the background in an editor before icon creation.

What happens to JPGs larger than 256 pixels?

The converter thumbnails them to fit inside 256 pixels. Our 640×480 source became a 256×192 icon entry.