That chart is a conglomeration of Local+State+Federal spending. Obama has no direct control over the first 2 so this does not prove your assertion that Obama is spending less. It's a good try to show the graph but to prove your assertion you would need a graph and statistics that actually back up your claim. This graph doesn't do that.
Here are the numbers for Federal spending: Keep in mind these numbers below are "net" outlays, "gross" outlays will be quite a bit higher.http://www.whitehouse.gov/sites/default/files/omb/budget/fy2013/assets/hist01z1.xls
2008: 2.982 T
2012: 3.795 T (Projected)
2017:4.531 T (Projected)
There are also plenty of websites to get numbers/graphs/outlooks/projections and historical data from. CBO/U.S. Dept of the Treasury etc.