Decrease size of unnecessarily large photos and videos (especially on the home page)

[bradygm]

This will help with the load times of our pages.

[bradygm]

Use this tool for more insights of speeding up our webpage load times: https://developers.google.com/speed/pagespeed/insights/?url=theairlab.org

[smash0190]

Updates?

[jfkeller]

In this commit b58ea12 I reduced the size of the main gif from 23 MB to 15 MB and the tartandrive image from 948K to 84K so that it is about the same size as the other images in the highlighted posts section of the home page.