How to make an image background transparent for free (and save a real transparent PNG)

First: transparency lives in the file format

Every pixel on screen has red, green and blue values. Transparency needs a fourth value per pixel, alpha, which says how see-through that pixel is. Only some file formats can store alpha, so however well you remove a background, saving in a format without alpha throws the transparency away.

Editors show transparent areas as a gray and white checkerboard. Paint has done this since the update announced in September 2023 (version 11.2308.18), which also let it open and save transparent PNGs.

The three ways background removal works

AI subject detection finds the main subject - a person, an animal, a product - and removes everything else. Busy backgrounds are fine and it takes one click, but zoom in on fine edges such as hair or glass before you rely on the result.

Connected area starts where you click and selects similar colors that are joined to that spot. GIMP's Fuzzy Select (magic wand) works this way, and so does Instant Alpha in older macOS Preview, which picks the matching colors next to where you drag. If the logo splits the background into separate pockets, you click each pocket.

Color key removes every pixel close to the chosen color anywhere in the image. GIMP's Color to Alpha, PowerPoint's Set Transparent Color and this site's image converter work this way. On a flat background it is the fastest and cleanest, but if the background color also appears inside the picture, that goes transparent too.

So for pictures that repeat the background color inside - a logo with white lettering on white, a stamp with a white rim - use connected area or AI. The other way round, when a logo has lots of small gaps between letters that all need clearing, a color key does it in one go where connected area needs a click per gap.

On Windows with nothing to install: Paint and Photos

Paint (Windows 11)

Windows 11 Paint has had an AI Remove background button since the update announced in September 2023 (version 11.2306.30). Paint updates through the Microsoft Store, so an up-to-date copy needs nothing extra.

1. 1Open or paste the picture in Paint.
2. 2Click Remove background in the toolbar. The subject stays and the rest turns into checkerboard (transparent).
3. 3To work on part of the image only, make a rectangle selection first, then click the button.
4. 4Save it as PNG.

Photos app

The built-in Photos app can remove backgrounds as well. It was announced for Windows 11 in November 2023, and in February 2024 for Windows 10 with Photos version 2024.11020.21001.0 or later (starting with the Release Preview channel at the time). Open the photo to edit it, choose the Background panel, then Remove, then Apply. Replacing the background with a flat color is in the same panel.

PowerPoint and Word (Office)

If the picture is going into a slide anyway, Office's background removal is handy. It shades what it will remove in magenta and lets you fix mistakes with a pencil. Labels follow Microsoft's help pages.

1. 1Select the picture, then Picture Format → Remove Background.
2. 2Magenta marks what will be removed. If something you want is magenta, use Mark Areas to Keep; to remove more, use Mark Areas to Remove.
3. 3Click Keep Changes.
4. 4To get a separate file, right-click the picture, choose Save as Picture and save as PNG.

For a logo on a flat background you can also use Picture Format → Color → Set Transparent Color and click the background once. That is the color key method, so the same color inside the logo goes too, and as Microsoft's help notes you can only make one color transparent per picture.

Mac and iPhone

On a Mac, the Preview app's Remove Background button does it in one step. If Preview asks whether to convert the document to PNG, say yes - that is what keeps the transparency. The older Instant Alpha tool selects the colors joined to where you drag, and Delete removes them: a connected-area method.

On an iPhone, touch and hold the subject of a photo until an outline appears. From there you can copy it into another app, share it, or add it as a sticker.

Browser tool and Python

This site's image converter (no upload)

Logos and signatures on a flat background can be done with Remove background in the image converter. The file is processed inside your browser and never uploaded.

1. 1Drop the image in and choose PNG or WebP as the output.
2. 2Turn on Remove background and click the background in the preview with the eyedropper.
3. 3Adjust tolerance (default 30): raise it if background is left over, lower it if the picture starts disappearing.
4. 4Download.

It uses the color key method, so it removes pixels close to the chosen color across the whole image (per its source code). If the logo repeats the background color inside, you will get holes as in the figure above; use Paint's AI removal or a connected-area tool for those. At the edges it fades pixels just outside the tolerance to partial transparency so the outline is less jagged.

Online AI background removers

The background-removal sites you find by searching use AI and do a good job, but your photo is uploaded to their servers. For ID cards, family photos or work material, use something that runs on your own PC: Paint and Photos above, or Python below. Free resolution and usage limits differ from site to site, so check before you rely on one.

Python: many images at once (rembg)

For dozens of photos, the open-source AI remover rembg is convenient (MIT license, Python 3.11 to 3.13). It downloads its model on first use and runs locally after that. Commands follow the official README.

pip install "rembg[cpu,cli]"

# one image
rembg i photo.jpg photo-cutout.png

# a whole folder
rembg p input_folder output_folder

For a flat-background logo done the connected-area way, Pillow's floodfill takes a few lines. It starts from the top-left corner and makes only the joined, near-white area transparent. The comparison figure above was checked with this code.

from PIL import Image, ImageDraw

im = Image.open("logo.png").convert("RGBA")   # add an alpha channel
ImageDraw.floodfill(im, (0, 0), (255, 255, 255, 0), thresh=30)
im.save("logo-transparent.png")                  # saving as JPG would fail

When it doesn't work

• The white background is back after saving — it was almost certainly saved as JPG. Check that the file ends in .png and save again.
• The logo has holes in it — that is the color key method at work. Redo it with connected area or AI removal.
• A white fringe remains around the edges — edge pixels blended with the white background fall outside the tolerance. Raise the tolerance a little. GIMP's Color to Alpha is designed to turn that blended color into partial transparency.
• Only half of a gradient background disappears — color-based methods can't catch a background that shifts gradually. Use AI removal.
• A white box shows up in the document — the original JPG went in instead of the transparent PNG, or the background got filled on save. Insert the PNG that shows a checkerboard in the editor.

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