trauben-nuss

This plugin adds a abbreviation of the operating system (win, mac, linux, iPad, iPhone) to the body-tag. 
So if there’s a OS-specific difference, you can easily react to it by using the css-selector (e.g. “.mac”).
Next steps of this plugin: 
* adding a settings page 
* add the class to specified elements 
* add user-language-abbreviation to specified elements
let me know, if you wish something helpful.

OS Adder

Add the operating-system's abbreviation as a CSS-Class to the body-tag.

nivijah

This simple plugin adds two additional fields to the media window, that lets you set additional classes to images on top of the default ones.
After installation two fields will be added to the media window under an image, One for custom class for featured image, and the other for images who are added into the WordPress editor.
Multiple class should be seperated by “space”.

Custom CSS classes for images

This simple plugin adds two additional fields to the media window, that lets you set additional classes to images on top of the default ones.

OS Adder vs Custom CSS classes for images