I am assuming you are referring to Sonnet 2 by Shakespeare, no?
When forty winters shall beseige thy brow,
And dig deep trenches in thy beauty's field,
Thy youth's proud livery, so gazed on now,
Will be a tatter'd weed, of small worth held:
Then being ask'd where all thy beauty lies,
Where all the treasure of thy lusty days,
To say, within thine own deep-sunken eyes,
Were an all-eating shame and thriftless praise.
How much more praise deserved thy beauty's use,
If thou couldst answer 'This fair child of mine
Shall sum my count and make my old excuse,'
Proving his beauty by succession thine!
This were to be new made when thou art old,
And see thy blood warm when thou feel'st it cold.
If I tell you that this poem is about growing old, you should be able to pick out the images. I will help you get started.
Look in the first two lines. What do you think this image is? What are the 40 winters? Winter is a season that implies old age, everything is dead. So the person is 40 years old. What are the "deep trenches" in the brow? Wrinkles!
The question being asked is "What will you have to show for yourself when you are 40 years old?" Your youth will become a "weed" (another image). The answer is that it will not be your beauty, because by then, your eyes will be "deep sunken" and not too beautiful. What will be your legacy? Not your looks. But...........if you have a child, then your beauty will live on. It will not be a fading sort of beauty. It will be a beauty that transends physical beauty.
Now you should be able to pick out the rest of the images.