Something like this ?
What I dit :
- Colours / Invert
- Add Alpha Channel
- copy layer and name it 'white' (or something else)
- on layer white use the Fuzzy Select Tool on the white area outside the clothes (Threshold value 22,5)
- then : Select / Invert and delete the selected area
- on the original inverted layer : Colours / Color to Alpha
What I dit :
- Colours / Invert
- Add Alpha Channel
- copy layer and name it 'white' (or something else)
- on layer white use the Fuzzy Select Tool on the white area outside the clothes (Threshold value 22,5)
- then : Select / Invert and delete the selected area
- on the original inverted layer : Colours / Color to Alpha