Lady of Shalott

This picture picks out the following lines of Tennyson's poem, 'The Lady of Shalott'

"And down the river's dim expanse

Like some bold seer in a trance,
Seeing all his own mischance
With glassy countenance
Did she look to Camelot.
And at the closing of the day
She loosed the chain, and down she lay;
The broad stream bore her far away,
The Lady of Shalott."

It hangs on a bedroom wall in my MIL's house, and I have always wondered what it was.