I downloaded - https://www.pexels.com/photo/dawn-desert-dry-dune-273935/

I load the photo in Gimp with an Alpha Channel - all is fine Now I create a new layer - Black - and put it below desert photo - still fine

Now I use Fuzzy Select on the sky - then I Delete the selection, that seems fine except there is a very fine line between the desert layer and the black layer. It is on the desert layer and I have changed the Fuzzy Select options, have used Select by Color with the same Results. I have used the Bucket Fill and tried the Eraser on the selected area with the same results.

I have used the same process on Rocky Horizons and the Sky with no problem.

I am at a loss as to what is taking place, maybe the color of the desert? Anyone with an idea I would appreciate any help.

Thank you, Tenn_Guy

It is important that you consider each image individually and not just 'one-size-fits-all'. The border between land and sky contains 'anti-aliased' (semi-transparent) pixels, also a jpeg image will contain jpeg compression artifacts. A very common fix for this type of selection. see screenshot.

1) The default for fuzzy-select threshold is 15. That leaves that border of light coloured pixels you are seeing.

2) An improvement is made by increasing the threshold value , say to between 50 and 80. Still not quite there.

3) Select -> Grow selection by 1 or 2 to get a selection boundary on those solid pixels.

You can mix those steps, often a selection and a grow by 2 or 3 pix works. Not too much though, or you will get a 'jaggy' border.

Thank you...

Select -> Grow selection This did the trick and solved the problem I was having. The default in 2.10.20 is "5 pixels" and that worked on the first try.

Thank you again, Art