You'd better ask on the English-only forum, but I'd say 'no, not really'. A souvenir is a physical object you buy on holiday; a fridge magnet or a statuette may be souvenirs, at a stretch a postcard may be a souvenir, but IMO not a picture you took yourself, all the more so if it's in electronic form. 'Memento' is a much better option because it doesn't have the same implication of having paid for the thing, but I think this word is also more appropriate for a physical object. To be honest in many contexts I'd just say something alone the lines of 'This is a picture from our holidays (in France, in Warsaw).'I wonder if the word souvenir could be used in British English, in that context.