Generally, the technical [image quality][1] of a digital image (before we get to the post-processing stage) is the product of the characteristics of the lens and the recording medium, with an important dash of good technique from the photographer.

Lenses are covered under http://photo.stackexchange.com/q/25572/1943, but what about the other important component, the sensor? [DxOMark][2] famously publishes some measurements, but what's really important? Obviously [megapixels][3] are part of it, but what else matters? Are there non-lens camera features other than the sensor which can have a positive or negative effect on image quality?

Most importantly, what do these things look like in actual real-world images, and how can I recognize them by looking it photographs rather than just review charts and graphs?


  [1]: http://photo.stackexchange.com/questions/35827/what-does-iq-mean
  [2]: http://www.dxomark.com/
  [3]: http://photo.stackexchange.com/questions/14773/do-megapixels-matter-with-modern-sensor-technology