A little help with some sprites for my Rimworld mod, specifically bordering them

[Apposl]

I have 3 sprites that are essentially done but when I removed their original background, a white/grey pixel-wide haze was left behind bordering each of them. I need them bordered in black obviously and this is stumping me. I'm a little more focused on learning the XML/C# side of things so the detour into Gimp has been a bit of a headache. The pixels aren't even fully connected so I can't just use a Paint Bucket Fill in black on them and be done. Not sure if I'm looking at image artifacts left behind or what, as the original image was PNG and not the vector I've been told I should have been using. But I didn't mean to get into the art side of this so much.

Anyway, credit given if anyone is willing to help with this.

(If you're a bored artist and love doing this stuff though, I'd love to give this short race a few clothing options - just smaller versions of vanilla stuff.)

Happy weekend, everyone!

[Whale Cancer]

You should tweak your selection options when selecting the background you want to use. Be a bit more aggressive with it (i.e. slightly higher tolerance and enable anti-aliasing). Then, when you add your outline, do so using a style on the layer. In Photoshop this would be an 'outline' with the default 3px weight. You can try having the outline originate on the border of the image going both inwards and outwards rather than only outwards (the default behavior).

I know you said you use Gimp but I would be shocked if Gimp didn't have this same feature.

[Apposl]

Thanks so much, got it with your help!