"Convert to colors" problem (png)

[zed]

Try the attached file (not white rect - it is white tank with transparency to "Convert to colors" (png).
Result - image dublicated in one canvas.

[xnview]

sorry but what's the problem?

[cday]

Before:

FlipCycleTileLarge_2.png

Image > Convert to Colours -- Colours 256 -- Dithering None

FlipCycleTileLarge_2_256.png

Duplicated??

Edit:

Are you using XnView Classic or XnViewMP?

The XnViewMP function Image > Change color depth... converts the image transparency to white rather than black, resulting in a white rectangle as you posted above, as the source image is pure white:

FlipCycleTileLarge_2_XnViewMP_256.png