If you use the ezie extension to edit a GIF image, using GD (not imagemagick) and you add a png watermark with transparency areas, the transparency is replaced with white color.

Steps to reproduce

1. Disable imagemagick in image.ini.append.php
2. Create an image object uploading a .gif image
3. Edit the image with the ezie
4. Add the PHP elephant watermark
5. Apply the watermark
6. Save the image
7. Verify that the image now have a white box were it should be transparent