By script-fu method:
1. Open/Load the image to which you want to add the border into gimp
2. Click on Filters -> Decor -> Add border -> Give X,Y(breadth,width) value & select the color -> OK
Note: This method will increase the dimension of the existing image by the value you given in X,Y value. To repeat/increase the border size use ctrl+f
3. You can add other border types like Fuzzy border which is available in the same menu as above
By shrink & layer method:
1. Open the image in gimp, select the full image ctrl+a.
2. Shrink the image using Select -> Shrink
3. Create a new layer with default dimension by Layer -> New Layer
4. Invert the selection by Select -> Invert or ctrl+i
5. select the paint bucket tool, select either color or pattern, then click on the border region
Note: This method will shrink the visibility of the original image dimension by the value give in shrink.
1. Open/Load the image to which you want to add the border into gimp
2. Click on Filters -> Decor -> Add border -> Give X,Y(breadth,width) value & select the color -> OK
Note: This method will increase the dimension of the existing image by the value you given in X,Y value. To repeat/increase the border size use ctrl+f
3. You can add other border types like Fuzzy border which is available in the same menu as above
By shrink & layer method:
1. Open the image in gimp, select the full image ctrl+a.
2. Shrink the image using Select -> Shrink
3. Create a new layer with default dimension by Layer -> New Layer
4. Invert the selection by Select -> Invert or ctrl+i
5. select the paint bucket tool, select either color or pattern, then click on the border region
Note: This method will shrink the visibility of the original image dimension by the value give in shrink.
