Här kommer en fix jag fann på internet och som fungerade för mig på en testbild.
http://objectmix.com/graphics/138623-select-area-shape.html
Here's a quick, flexible method.
Find a picture of a heart on the Internet, preferably one that is solid
colour.
Drag and Drop the Internet image straight from your browser into the
image you are working on.
You should now have an image of the heart over the top of your other image.
Layer -> Layer To Image Size
Layer -> Scale Layer
until the image is the correct size.
Select -> By Colour and click on the red of the heart, and you should
now have a heart-shaped selection.
(You can smooth the selection by Select -> Feather, increase the
selection by Select -> Grow and decrease the selection by Select -> Shrink.)
Click on the eye beside the "misc-thum.gif" Layer in the Layer Dialog.
This will hide the heart. Now left-click on the image Layer you want to
work on to select it. the heart selection will follow you to the new
layer, and you can use it to copy, paste or even selectively apply filters.
Hope that helps?
Joal Heagney
PS: Also look in the Gimp documentation for the tutorial on Layer Masks.
If you want to e.g. make a heart-shaped border around a portrait, layers
are an easier way to do this.
För mig så blev "fel" yta pixelerad, så du inverterar du bara markeringen, eller markerar allt utom hjärtat på orginalbilden.
Mvh