From inside a contraption instance, "card" refers to the contraption instance itself; this is handy if you want to send events to the "external" scripts on the contraption or inspect default properties like .locked, .show, or .font.
If you want to refer to the card within which a contraption resides, you can generally use "deck.card". Strictly speaking, "deck.card" is the active card on the deck; the card the user is looking at. This will only be distinct from the contraption's parent card if the contraption is being sent a synthetic event from some external script.
A different angle to consider would be prompting the user for a destination card when importing an image. You could, for example, use alert[] in "choose" mode to select cards from the deck by name, using the current card as a default:
alert["pick a destination card:" "choose" deck.cards deck.card.name]
The downside to the above is that if a user hasn't given cards logical names they're "picking blind", which can be error prone. Every design problem is fractal in nature...