Corrupted PNGs when XnView is closed too early

[larsen]

This is similar to a previous problem: http://newsgroup.xnview.com/viewtopic.p ... 53#p107611

- Make a screenshot by pressing Alt+Print
- Paste via Ctrl+Shift+V into XnView
- Save as PNG
- Close XnView

You get asked if you want to save the file (strange because you just have saved the file, but explainable later on).
When you re-open the file, it is ok to some line and afterwards just "repeats" itself.