# in your controller ...
BLANK_GIF = Base64.decode64("R0lGODlhAQABAPAAAAAAAAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==")
render text: BLANK_GIF, type: 'image/gif'
# in your controller ...
BLANK_GIF = Base64.decode64("R0lGODlhAQABAPAAAAAAAAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==")
render text: BLANK_GIF, type: 'image/gif'