Looking at the hair example, this is the issue here:
So let’s download it and get it into GIMP. Once loaded into GIMP, change to RGB mode:
Go to the channels tab here:
And toggle Alpha channel off. This means that we will only edit the other channels RGB:
If we hide the Alpha channel, you can see there the pixels that transparent on that edge are white hence the white artifact when rendering with linear filtering:
To fix this, we can use the a tool that was linked in the article called G’MIC
Or flood fill the rest of the image to black. I’m going to use the G’MIC tool (https://gmic.eu/) for GIMP as it works better for full colour images: (on Mac, you can download this version of GIMP as it has G’MIC included as default: https://www.partha.com/)
Right click on the layer and Add Layer Mask:
Select Layer’s Alpha Channel:
Open G’MIC and search for Solidify:
Default settings are fine:
It won’t look like it has changed but when you toggle the Alpha channel on and off:
Export as PNG and upload to the project:
