I'm looking for a PNG viewer for Windows that is transparent for the transparent parts of the picture - that is, we can then see the other windows below.

It should be something like this:

Normally, the transparent background is displayed gray But I want the background to be really transparent!
Normally, the transparent background is displayed gray / But I want the background to be really transparent

Use case: I need to align my live micrsocope image precisely to a shape of a PNG image. I could draw the edges of the image with some screen scribbling software, or just display my shape as a PNG image with alpha channel. It seems very straightforward that a PNG viewer should support that, but I haven't been able to find one with this feature.


  • (preferrably) free software which displays the alpha channel of an image as transparent.
  • It would be nice to scale and freely rotate the image when viewing it

Research so far

  • Coding something in this direction also seems possible (see e.g. here). But there has to be a out-of-the box solution!
  • In this post, they suggest using software to make one window semi-transparent. This is a halfways solution for my needs (right now I'm using Glass2K)
  • In the same post, they mention a software called Custom Desktop Logo which seems to be something in the right direction, but it doesn't work for me on Windows10.
  • I'm sorry for the ugly formatting. SE forbids more than 2 links for newbies like me, so please upvote so that I get more reputation and make nicely formatted posts :)
    – poppie
    Aug 14, 2016 at 9:48
  • A transparent web-browser would be a particularly cool and useful solution to this. The webkit rendering engine can do this (confirmed via PhantomJS) so there's no fundamental reason why browsers which use webkit - such as Chrome and Safari - couldn't optionally have a transparent background.
    – Antony
    Aug 17, 2016 at 11:11

3 Answers 3


If you install, python 2.7 & wxPython plus the Docs & Demo package you will find that you have, in the demos package a demo called ShapedWindow that does almost exactly what you are asking for. (There are also demos of AlphaDrawing that might be helpful)

  • Free, Gratis & Open Source
  • Cross Platform
  • Since it is python it is small, 136 lines, and you should be able to adapt it quite easily.
  • You can extend it to be able to change images, zoom, rotate, etc.

The demo running over the demo

Demo in action


Work is ongoing to make wxPython available for Python 3.x but it is not yet in a released state.


It's a bit of a hack, but here's a transparent browser


(Electron/Chromium based)

Transparent browser


I know it's a bit late, but maybe this would be interesting for people coming to this page while searching for a solution for exactly this problem.

One Photo Viewer can do exactly that, i.e. show png pictures with transparent alpha channel.

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