Athbhliain faoi mhaise dhaoibh uilig! Actually, ‘pictiúr’ is in the genitive case here, but it’s genitive plural, rather than genitive singular (like in “leithreas na bhfear” – men’s toilet = the gents). That’s also the reason why there’s no lenition on “pictiúr”. As a rule, nouns following a feminine noun (like ‘sraith’) are lenited, but that does not apply if they are in plural (also “sraith clár”, not “chlár” – “a series of programmes”).