The greyscale imaging performance of a total of 17 preclinical transducer/scanner combinations were measured over a period of 10 years. These comprised nine single element transducers and eight array transducers with nominal central frequencies ranging between 15 and 55 MHz, and were from four commercially-available preclinical ultrasound scanners. Performance was assessed using a single figure of merit, the resolution integral, using measurements acquired from images of a test-object, the Edinburgh Pipe Phantom. Two further parameters were derived from the resolution integral: characteristic resolution and depth-of-field. Our results demonstrate that 1) resolution integral values of the array transducers were greater than single-element transducers, and 2) the array transducers demonstrated greater depths of field than the single-element transducers of the same nominal frequency. Moreover we demonstrate that use of this single figure-of-merit enabled identification and quantification of changes in imaging performance of preclinical transducers over a 10-years period.