Lossless-ly optimize JPG image

Ran "jpegoptim --strip-all" on the image.

Size went from 28142 bytes to 11433 bytes (59% reduction).
Lossless-ly optimize GIF image

Ran "gifsicle -O2 -b" on the image.

Size went from 3996 bytes to 2960 bytes (26% reduction).
Lossless-ly optimize PNG images

Ran the following on these images:

- pngcrush -q -rem gAMA -rem alla -rem text
- optipng -o9 -q
- advpng -z -4 -q

Sizes went from:

- 6153 bytes to 2077 bytes (66% reduction)
- 6413 bytes to 2216 bytes (65% reduction)
- 1789 bytes to  643 bytes (64% reduction)
- 7383 bytes to 3423 bytes (54% reduction)
- 4765 bytes to 1555 bytes (67% reduction)
- 5197 bytes to 1730 bytes (67% reduction)
- 4765 bytes to 1555 bytes (67% reduction)
Merge pull request #2079 from fmarier/optimized_images

Optimized images