Picture 4a

Some young girls have come to the village well/fountain for water. Funny way of carrying things, on your head. People still do that in some parts of the world. Good for posture, makes you stand up straight and walk upright, instead of shuffling along, moaning about how hard everything is. It's very difficult to complain when walking with a jar on your head. That's why they don't moan = οὐκ οὖν στενάζουσιν, not like old Dikaiopolis, and especially ὁ Ξανθίας ὁ ἀργός (lazy Xanthias)

One girl is filling her jar at the fountain while the others are still waiting [their turn chatting].
μία μὲν κόρη πληροῖ τὴν ὑδρίαν πρὸς τῇ κρήνῆ, αἱ δὲ ἄλλαι ἔτι μένουσιν.
 
 Compare: 
Who? (nominative) τίς;
What? (nominative) τί;
Who is there? What is there?
nominative plural:
the girls     αἱ κόραι
people       οἱ ἄνθρωποι

(Whom?) or (like here) What? (accusative) τί;
What do they carry?
accusative plural:
the waterjars   τὰς ὑδρίας
the stones       τοὺς λίθους

Where to? ποῖ; (Movement towards is always expressed by the accusative case form)
Where do they walk [every morning]?
accusative singular:
the girls   βαδίζουσιν πρὸς τὴν κρήνην.
farmer and slave   βαδίζουσιν πρὸς τὸν ἀγρόν

Where? ποῦ; Position, usually expressed by the dative
Where are people?
dative singular:
at the well (f)        πρὸς τῇ κρήνῃ
in the field (m)       ἐν τῷ ἀγρῷ
under the tree (n)  ὑπὸ τῷ δένδρῳ
 
Remember, Chapter 1a. Where does Dikaiopolis, an Athenian, live? Where does he not live?
dative plural:
in the fields (=country) (m) ἐν τοῖς ἀγροῖς
not in Athens (f) οὐκ ἐν ταῖς Ἀθήναις

What do we see in the picture? τί βλέπομεν ἐν τῇ εἰκόνι;
 Note:  
The dative case (the to-whom do you give?) singular forms always end in iota,
subscript for 1st (or -a) and 2nd (or -o) declension words
ἐν τῷ οἴκῳ in the house
τῇ Μελίττῃ for/to Melitta (the daughter introduced in chapter 4)
real iota for the 3rd declension words (all else).
ἐν τῇ εἰκόνι in the picture.
τῷ παιδί for/to the child, boy
προσχωρεῖ τῷ βοΐ he approaches the ox
τί οὖν βλέπομεν ἐν τῇ εικόνι;
κρήνην
ὑδρίας
κόρας
γυναῖκας
ποῦ εἰσιν αἱ κόραι τε καὶ αἱ γυναῖκες;
πρὸς τῇ κρήνῃ
τί ποιοῦσιν; (what are they doing right now?)
ὑδρίας φέρουσιν,
μένουσιν (are waiting their turn),
λέγουσιν and maybe φλυαροῦσιν (are talking nonsense)
τί ποιοῦσιν; (what do they do at the well, though not right now, except for one of them?)
ὑδρίας πληροῦσιν.
 
  Remember:  
ἡ κόρη the girl
ἡ ὑδρία the water-jar
ἡ κρήνη the fountain, well
πληροῦσιν (short for πληρό-ουσιν just like ποιοῦσιν is short for ποιέ-ουσιν) they fill
πρός towards (+ accusative for movement towards, into, onto etc.)
πρός at, by, next to (+ dative case form for position at, in, under, on.....)