Cut a picture to a circle

Procedure: Cut a picture to a circle
Word of caution: there are no circular images, to get a circular images the corners are transparent, so that only a circle shows. Tools → Selection tools → Elipse select If you want a perfect circle Windows →  Dockable dialogs '→ 'Tool options - tick the "fixed", select "aspect ratio' and enter "1:1". Select '→ 'Invert (or Ctrl-I) Edit '→ 'clear '(or "Delete" key). You should have your central circle left, surrounded by a checkerboard pattern. I'mage '→ 'autocrop image Remember JPEG doesn't support transparent images...
 * 1) Add a transparent layer Right Click [on image]   Layer -> Transparency -> Add Alpha Channel 
 * 2) Create a circular selection.
 * 1) Invert the selection, so everything is selected, except your circle.
 * 1) Erase the selection
 * 1) Reduce the checkerboard to the minimum by auto-cropping the image
 * 1) Save image in a format that supports transparency, like PNG, GIF or XCF