This photo is definitely a composite.

• You can't see the Milky Way until some time around astronomical twilight (when the sun is 12°–18° below the horizon). The post-sunset clouds in the picutre are sometime in the civil or early nautical twilight. During nautical twilight, the horizon is clearly visible, but you need supplemental lighting to see any details near or far (you can't make out text on a newspaper during nautical twilight, for instance).
• For instance, where I live at 28° N latitude (central Florida, USA), as I post this in mid September, my astronomical twilight begins about 50 minutes after sunset (and ends about 50 minutes before sunrise).
• For London, UK, at the same date, astronomical twilight begins about 70 minutes after sunset (and ends about 70 minutes before sunrise).

With that in mind, imagine what approximately 1 hour after sunset looks like to you. It's dark. You don't see any high-atmosphere sunlight reflecting off clouds.

• The atmosphere doesn't transition like that. You don't see pitch black night sky only 20 — 30 degrees above the horizon. As a matter of fact, shortly after sunset, the antipode (directly opposite the point of the sunset) is slightly brighter than the local zenith You can't see the Milky Way "feathered" into the atmosphere like that.

• If there's enough light to see the hand lit like that in the foreground, then it was probably taken during civil or nautical twilight. The sky will still be blue (darkest near zenith), and you'd probably see a few of the brighter stars, and any planets that might be up. But again, definitely no Milky Way.

These are examples of what twilight really looks like (I tried to find shots that appear to be as late as possible after sunset):

^{Photo by Bill Abbott from Wikimedia Commons, CC BY-SA 2.0}

^{Photo by Adrian Pelletier, CC0 1.0 (Public Domain)}

This photo is definitely a composite.

• You can't see the Milky Way until some time around astronomical twilight (when the sun is 12°–18° below the horizon). The post-sunset clouds in the picture appear to be some time in the civil (sun 0°–6° below horizon), or early nautical twilight (sun 6°-12° below horizon). During nautical twilight, the horizon is clearly visible, but you need supplemental lighting to see any details near or far (for instance, you can't make out text on a newspaper during nautical twilight).
• As an example, where I live at 28° N latitude (central Florida, USA), as I post this in mid September, my astronomical twilight begins about 50 minutes after sunset (and ends about 50 minutes before sunrise).
• For London, UK, at the same date, astronomical twilight begins about 70 minutes after sunset (and ends about 70 minutes before sunrise).

With that in mind, imagine what approximately 1 hour after sunset looks like to you. It's dark. You don't see any high-atmosphere sunlight reflecting off clouds.

• The atmosphere doesn't transition like that. You don't see pitch black night sky only 20 — 30 degrees above the horizon. As a matter of fact, shortly after sunset, the antipode (directly opposite the point of the sunset) is slightly brighter than the local zenith You can't see the Milky Way "feathered" into the atmosphere like that.

• If there's enough light to see the hand lit like that in the foreground, then it was probably taken during civil or nautical twilight. The sky will still be blue (darkest near zenith), and you'd probably see a few of the brighter stars, and any planets that might be up. But again, definitely no Milky Way.

These are examples of what twilight really looks like (I tried to find shots that appear to be as late as possible after sunset):

^{Photo by Bill Abbott from Wikimedia Commons, CC BY-SA 2.0}

^{Photo by Adrian Pelletier, CC0 1.0 (Public Domain)}