How do you up load a pic edited in gimp to Facebook?

Simply save the picture in My Pictures as a PNG or JPG when you save your finished image. You can do this by typing in your image title when the save screen comes up and adding '.png' or '.jpg' to the end. Then go to facebook.com and upload the picture as you would normally. You can do that by clicking 'Photos' on the left side of the screen under your profile picture and then clicking 'upload photos'.