Make website images same size

[jwflory]

Summary

Make the three logos we use at the bottom of our website (RITlug logo, GitHub, Open Source Initiative) all the same size

Details

The size of the three images isn't consistent and it makes the spacing a little old when they're viewed horizontally.

The three images should all be the same size so the boxes are symmetrical.

Action

Set the same width and height on all of the images (or find alternatives for the logos if they don't scale correctly)

[ct-martin]

cc #72

[ct-martin]

PR didn't autoclose, fixed in #88