We develop a number of analogies between texts and images, where different pixel-brightness levels (or gray values) in an image correspond to different linguistic elements of some level (such as letters, symbols, words, etc.) in a text. This correspondence is possible only in the case of discrete structures such as digital images. A number of practical recipes for converting two-dimensional images into one-dimensional linear chains of pixels (i.e., ‘texts’) are discussed. In particular, this can be consideration of separate rows (or columns) in an image – or a series of sequential rows (or columns) in it, where a sequential number of pixel in a ‘one-dimensional image’ is analogue of a position of linguistic element in a text. The advantages and shortcomings of these recipes are analyzed. Besides, we introduce analogues of the statistical-linguistic notions of ‘vocabulary’ and ‘rank dependence’ in the case of images. Then we clarify the possibilities for application to digital images of standard statistical-linguistic techniques for detecting keywords in texts. In particular, we remind of the phenomenon of clustering of words in a text, which is very weak or absent for so-called function words – and pronounced for keywords. A simplest clustering parameter R is introduced that relates to the first statistical moments of the probability distribution for the waiting times of a given word in a text. It quantizes the scale of the above phenomenon for this word. After that, we analyze the latter phenomenon in the ‘texts’ that correspond to two different digital images. Our main result is that the ‘texts’ corresponding to a pure white noise and a simple informative image differ notably by their R -parameters associated with different ‘words’ (i.e., brightness levels). A possible meaning of ‘keywords’ in an image is discussed, which can be associated with some ‘semantic load’ of the appropriate brightness levels. We also advise to check the availability of long-range correlations among the same brightness levels in an image. This can be done according to one of standard techniques known for the studies of correlations (e.g., fluctuation analysis or detrended fluctuation analysis). Key words : statistical linguistics, natural language processing, clustering, keywords, digital image processing.