Usually not conclusively. But with a digital image, you can often find signs of editing by close inspection.

Useful checks include:

• Raising gamma or otherwise brightening dark areas to reveal mismatched background tones around a pasted object.
• Viewing at 100% or higher magnification and inspecting edges for halos, rough cutout borders, or other edge artifacts.
• Looking closely for repeated textures or cloned patterns that seem natural at normal size but repeat at high zoom.
• Checking whether nearby background areas should have been affected by the object and whether that interaction looks believable.

That said, not all hoaxes require image editing. A fake “UFO” could simply be a physical object, like something suspended on fishing line and photographed out of focus. In those cases, software analysis may not reveal manipulation because the deception happened in-camera, not in post-processing.

So the answer is: sometimes you can show strong evidence of editing, but proving it conclusively is rare.