12-11-2016, 09:35 AM
That image started off as a vector (svg) graphic so the best way would be a vector editor such as inkscape
However
Yet another way using Gimp and this only works because the background is white.
Make a rough selection http://imgur.com/9l2HIdr.jpg
Fill that selection - top transparent layer - with blue http://imgur.com/8QPinwQ.jpg
Change the layer mode to screen. http://imgur.com/CwKf4mt.jpg
This avoids having to mess with the thin border of semi-transparent green pixels left over from a color selection.
But there might be other reasons, a distinct shape of South America, is needed in which back to previous method.
However
Yet another way using Gimp and this only works because the background is white.
Make a rough selection http://imgur.com/9l2HIdr.jpg
Fill that selection - top transparent layer - with blue http://imgur.com/8QPinwQ.jpg
Change the layer mode to screen. http://imgur.com/CwKf4mt.jpg
This avoids having to mess with the thin border of semi-transparent green pixels left over from a color selection.
But there might be other reasons, a distinct shape of South America, is needed in which back to previous method.