Transparency for .png and .tga is corrupted

[esassaman]

All my alpha channels are not displaying correctly both in the Manage tab (all the thumbnails) and when editing an image with alpha, for both .png and .tga format files. Furthermore, when saving as a PNG, with transparency set to alpha channel, it is lost and is saved as pure black.

**EDIT**

The problem was caused by File/Preferences/File Format Preferences/PNG, then make sure Load and save transparency to / from layer transparency is selected.