Kodak FZ55 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor . On the other hand, Nikon S220 has a
10.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Kodak FZ55's sensor provides 6MP more than Nikon S220's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the FZ55 and S220 sensor size comparison.
Sensor Size and Resolution Comparison image of Kodak FZ55 and Nikon S220 Cameras
Kodak FZ55 and Nikon S220 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Kodak FZ55
or the
Nikon S220 ,
including hyperfocal distance.