Methods of obtaining images and their quantitative analysis should be developed in order to analyse an influence of properties of cellular skeleton on mechanical properties of a tissue. The paper presents visual texture analysis method for quantitative measurements a mean cell size from confocal images of potato and carrot tissue. The confocal images were obtained using the confocal laser scanning microscope (CSLM) and segmented using procedure developed. The accurate mean cell size obtained after segmentation was compared with a size of the structural element of a closing morphological operator applied to the same images. It was obtained that visual texture analysis allows obtaining quantitative information about the size of the cells within images obtained by the CSLM. The quantitative information about the mean cell size within the confocal image can be obtained by both calculating an inflection point on G(i) curve or by a grey level variation g(i) analysis. Common recalculation equation for obtaining the mean cell size can be used for both materials potato and carrot.