“Intergraphicality” might be a good way to describe it. Since intertextuality is so broad, it would be useful to have more nuanced terms to describe particular kinds of intertextuality.
Typically, I’ve seen this simply called “visual intertextuality.” The concept of intertextuality is all-encompassing. If it means “the shaping of a text’s meaning by referring to its difference/similarity to other texts,” this becomes a very broad definition. It is even broader than this. Some critics, such as Roland Barthes, consider that all signs (visual and otherwise) and even events of history can be read as texts. If you follow this line of thinking, all visual, textual and audible representations have a “textual” aspect to them. I’ve read analyses of visual art where the language used to describe its “visual intertextuality” is the same as if it were describing a literary text. If all signs are textual, they all can be discussed in terms of intertextuality.
But, the broadness of the term has received some criticism because there are nuances to this idea of referring to other texts. An allusion is one example. This term existed long before the concept of intertextuality became a buzz word. An allusion is a kind of intertextuality. So, there are already existing terms which are more narrowly defined types of intertextuality. As far as visual types, I have not seen one widely accepted definitive term.
The only term I know of that comes close is “ekphrasis,” which is the act of describing visual art as literary. Since this is describing one art form in terms of another art form, it is intertextual by being interdisciplinary. I guess if you wanted to make this more precise, you might say “intertextual ekphrasis,” but intergraphicality works just as well. Who knows which terms will be coined and generally accepted?