Consider restoring border and margin for image editing

[nacin]

We lost the old Basic/Advanced TinyMCE editimage.html editing in 3.9. We brought back most of the "advanced" features like classes, but two things remain missing: margins and borders. This has been discussed extensively in #27366 and in IRC. We're still considering whether it comes back to core or if it's just a plugin. This ticket is for that.

[eablokker]

Here's my opinion on this:

Do not allow border color and border styles options.
When you give a user the option, they will use it and abuse it. It's this reasoning why we prefer not to give the option to change font sizes in the visual editor, or change typefaces. People will abuse it and turn their beautiful theme into an ugly mess. Just imagine, thanks to WordPress, blog posts with multicolored image borders and random border styles all over the place. Yuck. In my opinion border styles should only be controlled by the theme, and optionally by adding image CSS classes that the theme might provide. This is definitely plugin territory.

Do allow margin settings for top, right, bottom, and left.
Margins however do not have the same ability to uglify your theme. Potential for margin abuse is limited. It only changes positioning, thus keeping your theme styles intact and everyone is happy. Image positioning in the visual editor is always very tricky and kind of a pain in the butt. My opinion is that margins will help alleviate image positioning woes.

Not sure if margin values should be in px, %, or em units, or whether to give the option to choose the unit.

[nacin]

It looks like #27698 is going to let us build this as a plugin.

[nacin]

There will be a plugin. Closing this.

[Denis-de-Bernardy]

#27932 was marked as a duplicate.