I mage Pictures are important in science because people are naturally very good at interpreting images. When we observe the Sun, for example, a picture immediately tells us a lot about what is happening and whether our instrument is making sensible measurements. Images are particularly valuable for finding features, looking for changes, and for checking large volumes of data. A picture is truly worth many megabytes. But scientific measurements are more than just pretty pictures.
Measurements have to be quantitative.
Converting the values we get from an instrument into meaningful numbers in standard units is called calibration . For example, I keep my alarm clock at home set to the correct time, but my spouse keeps hers 5 minutes fast. When we make scientific observations we make the same sorts of adjustments, though the errors are not usually voluntary. Think about an image of the Sun that falls on a CCD camera with a million pixels. Or if we compare pixel 951 with pixel 952, they may give different readings for the same solar brightness - the sensitivity is different for each pixel.