Add a 1x1 black border to your screenshot from the command line.
Clone bordify into your workspace, cd into it, run bundle install, and add an alias to your bash_profile.
$ git clone https://github.com/bentarnoff/bordify.git
$ cd bordify
$ bundle install
$ echo "alias bordify='ruby ~/workspace/bordify/bordify.rb'" >> ~/.bash_profile
$ source ~/.bash_profile
bordify MY-SCREENSHOT.png
By default, Bordify will create a new image called MY-SCREENSHOT-BORDERED.png
bordify -o MY-SCREENSHOT.png
Using the -o flag will cause Bordify to overwrite the original image with the new bordered image.
bordify MY-SCREENSHOT1.png MY-SCREENSHOT2.png
Bordify multiple files.
bordify MY*
Bordify multiple files with the * wildcard.
bordify *
Bordify everything in the present working directory.