When scaled down edges looks jagged

[Ofnuts]

(03-11-2018, 12:46 AM)chrisj Wrote: Can I ask, what is the best way to change to another color other than black?

1. Remove any selection (in particular, not alpha to selection...)(*)
   
2. Alpha-lock the layer (click on the checkerboard icon on the "Lock" line at the top of the Layers list)
   
3. Bucket fill the whole layer, the alpha-lock will preserve the transparency of all layers.
   

(*) To be accurate you can have a selection, but all the pixels of the object (including its edge pixels) should be fully selected. For instance if you want to change the color of just the brown line, you can fuzzy-select it, and then Select>Grow by 2px to make sure to include all the edges.