There are a couple of different types of imaging satellites currently orbiting our planet. On one end of the spectrum are specialized satellites that gather very high-resolution imagery in which you can identify objects as small as 3 feet across. On the other are the lower resolution satellites that beam down photos of larger areas.
California company Planet Labs wants to fill the space in-between, by providing an affordable middle-of-the-road option for companies interested in using it. To that effect, they're planning on launching 28 tiny, mid-resolution satellites called "Doves" into space before the year is out.