This is the 950th most frequent Icelandic word.
ykkar
"Ykkar" means "your" (plural possessive) in English.
In this sentence, 'ykkar' again shows possession, specifying 'your' in the plural sense as it pertains to the pictures.
Ég mun sækja þangað allar myndirnar ykkar.
I will fetch all your pictures from there.
The word 'ykkar' is employed to inquire about possession, asking whether certain items can be attributed to the plural 'you'.
Er eitthvað í þessu húsi sem er ykkar?
Is there anything in this house that belongs to you?
Here, 'ykkar' is used to denote possession, indicating that the book does not belong to 'you' in the plural form (y'all).