Create CSS-Only placeholder images. I'm using the term "FPO" (For Placement Only) because "placeholder" is already a keyword in Sass and things would get confusing fast.
bower install sass-fpo --save-dev
npm install sass-fpo --save-dev
Make sure you add the installation directory (
node_modules by default, respectively) to your included paths in your sass config.
Import sass-fpo into your stylesheet:
If true, warns you at compile time that FPO elements are being used in the project. Defaults to
Creates the FPO image. Takes one
Map argument, that has four optional properties:
Number (Unitless) 
The size of the height, in relation to the width. For example,
1 will set the height equal to the width and
0.5 will set the height to 50% or the width.
The background color of the FPO image.
List ['bold 20px/1 sans-serif']
The font property to use on the FPO text.
The text to display in the FPO image.
This plug-in requires Ruby Sass >= 3.4 or LibSass >= 3.1.