raster format

What is a .G4 file?

G4 is Group 4 fax compression, a more efficient lossless method for black-and-white documents widely used in archiving and scanning.

Full name
Group 4 Fax
Developed by
ITU
Released
1984
Extension
.g4
MIME type
image/g4
Transparency
Varies

How to open a G4 file

G4 opens in fax and document tools; convert to TIFF/PDF for general use.

What G4 files are used for

Photos & web images

Share, post and embed pictures across sites and apps.

Editing & design

Work with the format in editors like Photoshop and GIMP.

Storage & archiving

Keep memories and assets in a widely-readable form.

Strengths & limitations

✔ Strengths✖ Limitations
Lossless — keeps full qualityNo transparency support
Excellent compatibilityLimited support — may need converting

Need more than a conversion?

Remove the background from G4 images, upscale to 4K, or generate new visuals with SharkFoto AI.

Frequently asked questions

G4 is Group 4 fax compression, a more efficient lossless method for black-and-white documents widely used in archiving and scanning.

G4 opens in fax and document tools; convert to TIFF/PDF for general use.

Yes — G4 preserves full quality with no compression loss.

Use SharkFoto's free tools — upload your G4 file and convert it to a more convenient format in seconds. It's free, processed securely and never stored.

No — G4 doesn't store transparency; convert to PNG or WEBP if you need it.