Query: Some experts believe comics is a combination of what two things?
Context: It is common in English to refer to the comics of different cultures by the terms used in their original languages, such as manga for Japanese comics, or bandes dessinées for French-language comics. There is no consensus amongst theorists and historians on a definition of comics; some emphasize the combination of images and text, some sequentiality or other image relations, and others historical aspects such as mass reproduction or the use of recurring characters. The increasing cross-pollination of concepts from different comics cultures and eras has further made definition difficult.