Losslessly compress images.

Before: 113 KB (115.942 bytes)
After:  91,2 KB (93.433 bytes)
Remove unused images.
Whitespace cleanup.
Minor CSS tweaks.
Fix all validation errors.

Move some inline CSS to style.css.
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.