Fujifilm S9800 has a 16.0MP 1/2.3" (6.17 x 4.55 mm ) sized CMOS sensor . On the other hand, Olympus FE-25 has a 10.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Fujifilm S9800's sensor provides 6MP more than Olympus FE-25'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 S9800 and FE-25 sensor size comparison.
Sensor Size and Resolution Comparison image of Fujifilm S9800 and Olympus FE-25 Cameras
Fujifilm S9800 and Olympus FE-25 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.