There are two ways to approach this question. The first way is by looking at definitions of literature put forward by those who study literature as a profession. For example, Chris Baldick's The Concise Oxford Dictionary of Literary Terms (2001) provides the following definition (emphasis mine):
a body of written works related by subject-matter (e.g. the literature of computing), by language or place of origin (e.g. Russian literature), or by prevailing cultural standards of merit. In this last sense, 'literature' is taken to include oral, dramatic, and broadcast compositions that may not have been published in written form but which have been (or deserve to be) preserved.
Academia has mostly concentrated on poetry, drama and prose fiction, but even when non-fictional works were included, these were still works that can be studied from a linguistic point of view.
For comparison, the definition in The Routledge Dictionary of Literary Terms (2006) by Peter Childs and Roger Fowler begins as follows (emphasis mine):
In present times generally taken to be imaginative compositions, mainly printed but earlier (and still, in some cultures) was oral, whether dramatic, metrical or prose in form. This is a relatively recent usage, having general acceptance in the European languages only from the nineteenth century. Earlier senses have been less restricted: for example, the body of writings in a language, artistic or not; and particularly, the study of such a corpus of written materials.
In other words, non-text compositions are excluded. (Oral compositions can be treated as text, as linguists do.)
The second approach is looking at what gets treated as literature (see What is literature?). However, even though literary theorists argue that you can't define literature by means of certain characteristics, they still assume that literature is textual and thus excludes the graphical and plastic arts.
Even the Nature article Is this cave painting humanity’s oldest story? referenced by the question describes the 44,000-year-old cave painting as "figurative art", not as text, writing or literature. (Even when it describes the cave paintings as "narrative artworks", the term "scene" seems to be preferred by the archaeologists.)