G4 to ICO conversion is the process of transforming an image encoded with the G4 (CCITT Group 4) compression format—commonly used for monochrome scanned documents and faxes—into an ICO file, the icon format used by Windows for application and favicon images. This conversion decodes the bilevel (black-and-white) raster data from G4, optionally processes sizing and color depth, and repackages it into one or more icon images inside an ICO container suitable for use as desktop or website icons.
Related guides
Practical guides to help you choose formats, preserve quality, and avoid common conversion problems.
WebP has quietly become the default image format of the modern web, delivering 25-35% smaller files than JPG and PNG with universal browser support. This 2026 guide covers current adoption stats, browser compatibility, WordPress integration, conversion workflows, and when to choose WebP over AVIF for optimal Core Web Vitals performance.
Read guide →Not sure whether to save your image as PNG or JPG? This detailed comparison covers compression, transparency, file size, web performance, and real-world use cases so you can pick the right format every time — with conversion links when you need to switch.
Read guide →Learn how to convert HEIC to JPG for maximum compatibility. This guide explains what HEIC is, why iPhones use it, the key differences between HEIC and JPG, and walks through every conversion method including online tools, iPhone settings, Windows, and Mac.
Read guide →Drag your .G4 file from your computer or use the browse function.
Confirm .ico as the selected destination format.
Click "Convert" and download your converted .ICO file once ready.
G4 files typically use the MIME type image/g4 and are encoded with CCITT Group 4 compression suited for black-and-white images. ICO files have the MIME type image/vnd.microsoft.icon and contain multiple images to support various icon sizes and color depths. ICO is commonly used in Windows applications and website favicons.
The ICO (.ICO) format is commonly used for image. Understanding its characteristics can be helpful when converting to or from other formats like G4.
While specific technical details aren't available here, ICO files generally serve the purpose of storing image effectively within their domain.
Our online G4 to ICO converter offers a seamless solution to convert your G4 image files into ICO format without installing any software. Designed for convenience and speed, this tool is ideal for users who need to generate high-quality icons from G4 files effortlessly.
G4 is a highly compressed monochrome image format mostly used in fax and scanned documents, while ICO is a versatile icon format supporting multiple image sizes and color depths. Unlike G4, ICO files are designed specifically for icons used in software and websites.
Keep original G4 TIFF pages at or below 1024x1024 pixels to avoid oversized ICO entries; icons are typically small so downsampling to 256x256 or lower preserves usability.
Preserve quality by raster-resampling using nearest-neighbor for pure bilevel images to avoid gray artifacts; for aesthetic icons, convert to grayscale or 24/32-bit color then apply anti-aliasing.
For multiple icons, batch-convert multi-page G4 TIFFs by exporting each page as a separate icon size, then combine them into a single ICO with multiple resolutions.
Format limitation: G4 is strictly bilevel (black-and-white); converting to full-color ICO requires adding color information (dither or recolor) which may alter the original look.
This converter saved me hours when creating icons for my projects.
Emma R.
Graphic Designer
Quick and reliable conversion from G4 to ICO without any hassle.
Mark L.
Software Developer
The online tool is straightforward and produces high-quality ICO files every time.
Olivia S.
UI Specialist
Start your free G4 to ICO conversion now.
Drag your file here to to upload.
Up to 250MB
Optimal file sizes: target 5–50 KB per icon size for web use and keep the combined ICO under ~200 KB for quick loading.