Meaning of "and light shows between his tightly buttoned torso and his father’s leg."

Question

It is a photo of a family. The wind puffs out the huge stiff curved sleeve of the woman’s dress, and brushes back off his forehead the long hair of the father’s boy who is turned towards the drama of his parents’ faces; though he is holding his father’s hand, he is separate from the group, and light shows between his tightly buttoned torso and his father’s leg.

This sentence is somehow unclear to me. Does it mean: There is light between his tightly buttoned torso and his father’s leg.?

Or does it mean: There is something between his tightly buttoned torso and his father’s leg that light shows that?

Source: The Children's Bach by Helen Garner.

Answer 1

The context of the quoted passage is that

Dexter found, in a magazine, a photograph of the poet Tennyson, his wife and their two sons walking in the garden of their house on the Isle of Wight.

So we can be confident that this is the photo:

It was taken c. 1862 at Farringford House on the Isle of Wight, and from left to right shows Hallam Tennyson (1852–1928), Alfred Tennyson (1809–1892), Emily Tennyson née Sellwood (1813–1896), and Lionel Tennyson (1854–1886).

There appears to be a shaft of light passing between Hallam and his father, but the way that this crosses the elder Tennyson's leg suggests that it is a light leak, an artefact of the photography process.

Answer 2

Gareth Rees found the photo itself, which answers your question about the meaning, but let's also clear up any doubt about grammatical ambiguity of the phrase.

You asked whether "light shows between his tightly buttoned torso and his father’s leg" could mean either of the following:

1. There is light between his tightly buttoned torso and his father’s leg.
2. There is something between his tightly buttoned torso and his father’s leg that light shows that.

If the latter meaning (2) were intended, then "shows" here would be used in a transitive sense, in which case this verb would need an object. For example, it might be "light shows grass between his tightly buttoned torso and his father’s leg" or even "light shows a gap between his tightly buttoned torso and his father’s leg", but in this case an extra noun (or pronoun or noun phrase) is required. Since there isn't one in the given sentence, "shows" must be used in the intransitive sense, which brings us to the first meaning (1) among the two you suggested.

Definition of show

transitive verb
1: to cause or permit to be seen
[...]

intransitive verb
1a: to be or come in view