Seven years ago photographer David Quentin began capturing surreal, alien-like scenes of rocks falling from the sky at locations across the UK.
It all started when the London-based photographer threw a stone into the air and took a picture of it to see how it looked.
What started as a "whimsical impulse" developed into Rocks In The Sky, a collection of images of pebbles and interesting lumps of stone shot on "very fast film" against empty landscapes.
Mr Quentin's images, which he posts on Twitter under the handle @_RocksInTheSky, have been taken in various places in the UK including in the Scottish Highlands, Hertfordshire and Gloucestershire.
Other images were taken in Douglas and Port Erin on the Isle of Man.
He continues to add images to the project.
"The project began as a whimsical impulse on a sunny day in the South Downs, and quickly became an absorbing technical challenge that used up many rolls of film, and is now a growing collection of what I think are quite striking images," says Mr Quentin.
"Sometimes people assume they must be Photoshopped, but that would be more of a technical challenge than what I actually do, which is throw the rock into the air - or ask a friend to throw it for me - and photograph it while it is up there.
"That way the light and shadow position themselves correctly on the rock without any further intervention."
The photographer adds: "If there is a trick to these shots it is in using very fast film.
"That way the shutter speed can be fast enough to give the rock that delicious impression of stillness, while the aperture is small enough to keep both foreground and background in focus.
"Then of course there is the question of composing the picture with the rock in exactly the right patch of sky, which has to be done quickly, because the rock is in motion and only up there for a short time."
"What do they show us?" asks Mr Quentin of the images.
"It seems to me that when artists show us rocks in the sky - Magritte's The Castle in the Pyrenees, or the film Arrival with its visiting spacecraft in the form of giant hovering menhirs - we see something which is alien and surreal, but at the same time achingly familiar," he says, making reference to artist Rene Magritte's surreal painting of a castle on a floating rock, and last year's sci-fi movie starring Amy Adams and its polished standing stone-like spaceships.
"I don't know why rocks in the sky somehow look like they actually belong there, but to my eye they very much do."
All images are copyrighted.