I have done nothing special to enable previews on Arch Linux.
I can confirm missing previews on neon unstable edition despite preview of images in Dolphin is enabled on both systems.

In D27181#672572, @papoteur wrote:

In D27181#672563, @bugseforuns wrote:

My screenshot is showing preview of the compressed file (source) as "destination".

Hi Patrick,
Is it different with the original ark?

My screenshot is showing preview of the compressed file (source) as "destination".

I have tested this patch myself on Arch Linux.
Previews of jpg flles don't work as expected,
the one below "Source" is not generated and below "Destination"
we see the preview of source file.

Probably this patch fixes bug 390488.

Patch also working on Neon unstable edition. :)

This patch fixes bug 418580.

Will popup menu show up if "Move files if on the same device" is selected and files are dragged to another partition on the same device?
If so, "Move files if on the same device" label is not accurate.

Tested this patch myself on Arch Linux.
It does not work when I eject an optical disc. It works when I unmount ("Release") the disc instead.
Dolphin switches to Home before I enter password to confirm unmounting of internal hard disk partition.

Apparently this patch will fix bug 158934.
With this patch, what will happen if the device is unmounted instead of ejected?

I'm not a software developer, but I applied Rok's patch on Arch Linux and it fixes the problem when unmounting/releasing ISO images.