There doesn’t seem to be a way to add images anywhere other than on the level of individual decks.
I have looked through the forum but couldn’t find anything related.
On Wiktionary there is a wealth of incredibly useful SVG (or PNG equivalents) of bronze inscriptions, seal script, and other historic characters. I would love to be able to insert them, or alternatively just link to individual images.
Here is an example:
Here is a link to an SVG file on Wikipedia:
https://upload.wikimedia.org/wikipedia/commons/2/21/%E5%8E%9F-bigseal.svg