I took a screen-shot of an image and want to edit it, but I am having a problem with edges, that it is ant-aliased. How can I remove anti-aliasing from that image?? I am using GIMP editor. Thanks in advance.
As others said, you usually want to keep the anti-aliasing.
If you want to remove it nevertheless, and if the image is on a uniform background:
1. Remove the background using Color to Alpha
- Add an alpha channel if necessary: Layer → Transparency → Add alpha channel.
- Fuzzy-select the background
- Select → Grow by two pixels
- Use Colors → Color to Alpha to remove the background (note down the RGB values of the color you removed)
- Select → None (important for what follows)
2. Change the opacity using a layer mask:
- Add a layer mask: Layer → Mask → Add layer mask and initialize to Transfer layer’s alpha channel.
- Use the Threshold tool (Tools → Color tools → Threshold) to threshold the layer mask (it should normally apply to the layer mask at that point, otherwise, click on the layer mask preview in the layers list).
- If/when happy with the result, Layer → Mask → Apply layer mask.
3. Restore the background
- Set the foreground color to the color your removed in the color-to-alpha step.
- Set the Bucket Fill tool to Behind mode (Mode: selector at top of tool options), and bucket-fill the layer.