Images
What is Transparency?
Also called alpha channel or transparent background.
Image transparency lets a background show through some or all of an image’s pixels, stored in an extra value per pixel called the alpha channel.
How it works
Most images store three values for each pixel: red, green and blue. Transparent images add a fourth, alpha, which says how opaque the pixel is. An alpha channel can represent fully transparent, partly transparent and fully opaque pixels.
Partial transparency is what makes cutouts look natural. Hair, soft shadows and anti-aliased edges fade gradually into whatever sits behind them. Without it, edges are either jagged or surrounded by a fringe of the old background color.
PNG and WebP are the usual formats for transparent images, with AVIF gaining ground on the web. GIF supports only on-or-off transparency, which produces hard, jagged edges around curves.
A practical example
A transparent product image can sit over a blue page while its soft shadow blends naturally into that page instead of showing a white box.
What to watch out for
JPEG doesn’t store transparency. Exporting a transparent picture to JPEG fills it with a solid background, and a checkerboard painted into an image isn’t real transparency.
Tools you can use
- Remove Background · Cut out people, hair and all
- Image Converter · Change an image from one format to another
- Circle Crop · Round profile pictures, transparent corners
- Add Border · Borders or pad a photo to fit a square post
Go a little deeper
- How to make a round profile picture
- How to make an image background transparent
- Why do images save as WebP instead of JPG?
- Why does my transparent PNG have a black background?
Common questions
Which image formats support transparency?
PNG, WebP, AVIF, GIF, ICO and SVG. PNG, WebP and AVIF support partial transparency; GIF only fully transparent or fully opaque pixels. JPEG and BMP in normal use don’t support it.
Why does my transparent image have a black background?
The program showing it doesn’t support transparency, or the image was converted to a format without it. Keep the PNG version and check the app accepts PNG.
Why is there a checkerboard in my ‘transparent’ image?
Some downloaded images have the checkerboard drawn into the pixels. It only mimics how editors display transparency; the background still has to be removed.