Add depth to the logo directory
Use imageMagick to change png to jpg

Force size of 115 px in width and 155 px in height since that is what we
are displaying on the website.
Homepage: replace team/advisor png's with jpgs

Also set the height/width.  This should save about 2MB on pageload
Merge pull request #39 from ScienceCommons/compress_images

Compress images