I assume they’ve invented photographs in star wars.
Moving photographs are to be seen in EP II’s deleted scene in Padme’s room on Naboo. (that said most deleted scene are not canon, it’s a grey area). There are photographs also in Rebels. (funnily there look like hand drawn cartoon)
The question would be: is it or not canon that Leia knows she was adopted before Luke told her the truth? As far as I know it is not canon for now. So we can only assume that Leia is refering to her adoptive mother (because when Luke asks her she should still believe that she’s her real mother. We don’t know if Bail told her the truth). End of debate for me unless there is something that contradicts that. One can always wondering about photographs or Force visions or anything else, but if we stick to what is told, then the logical thing is that she’s just talking about her adoptive mother. It’s just that Luke is turning his question from his point of view (from what HE knows) when he asks about her “real” mother.
But yes, it’s a problem with Lucas. Originaly she’d lived with her mother for two years before she’s adopted.