[Gimp-user] Gimp channel mixer

[Oxonian <forums gimpusers com>]

I'm trying to use the GIMP channel mixer to reverse the red and green channels
in a TIF image. I'm using GIMP 2.9.6.

After swapping the channels etc. and hitting OK, all that happens is that a very
small thumbnail appears in the top left corner of the main image. I can see that
the channels have been reversed in the thumbnail, but the main image remains
unaltered.

I cannot find a way to apply the changes to the main image, I'm very new to GIMP
and image editing software, so I hope the solution isn't something any ten year
old child could work out! Any help greatly appreciated

-- 
Oxonian (via www.gimpusers.com/forums)