Losslessly compress images.
Remove unused images.
Whitespace cleanup.
Fix all validation errors.

Move some inline CSS to style.css.
CSS cleanup and tweaks.

* add missing vendor prefixed properties
* be consistent with `color`
* sort properties by name
Remove unused images.
Recreate fireftpthumb as an 8-bit PNG.

It's half the size without any visual difference.
Switch to a single favicon.ico which includes 16x16 and 32x32 sizes.