Often times you’ll have an image, perhaps a logo, that you want to use on a website, and you’ll want that image to have a transparent background. Here’s how to make an image have a transparent background using a free drawing program called Paint.net (note this solution works on Windows only).
1. Download and Install Paint.net
First, you’ll have to download and install Paint.net if you don’t already have it. It’s a good free program to have if you don’t already have Photoshop.
2. Install the Grim Color Reaper Plugin
Next, you’ll need a plug-in curiously named the “Grim Color Reaper” (don’t ask me why it’s called that). Download it, unzip the file, and copy the .dll file to your desktop for now.
You install this plug-in simply by copying the .dll file into the “effects” directory where Paint.net was installed. In most computers, that directory is here: C:\Program Files\Paint.NET\Effects. If it’s not there, check out this link to help you install Paint.net plug-ins.
3. Open the Image
After it’s copied, re-start Paint.net and open the file that you want to make transparent.
4. Apply the Grim Color Reaper
Now, in Paint.net, select Effects -> Color -> Grim Color Reaper. You’ll see a preview of the image, with the transparent parts with a grey checkerboard pattern. In this case, the default settings are wrong; the image is transparent and the background is opaque (that might be okay with your image though). If it is not correct, select “Secondary Color” in the “What Color?” pulldown. You might also need to play around with the “Color tolerance” and “Consider transparent..” sliders to get the desired results with your particular image or logo.
When you get the opaque areas that you want, save the file as a .png.
This is really useful for logos and such. Let me know about your experiences or comments!