It was done with PHP using GD libraries... unfortunately, it wasn't as simple as just running some software to do it automatically.
The engineers who worked on it wrote all the code to create the images then used Amazon's Elastic Cloud service to do all the rendering of the frames. It was a massive amount of data to process! Paul Ericksen said comment on the video.
Kiva reveled a data visualization video showing what happens when 620,000 lenders fund 615,000 people in need around the planet. The video starts out slow, with just a couple data points, but quickly bursts into a hive of activity.