Either I'm missing something (or have something badly configured in my self-hosted blog network) or when I'm uploading a transparent
.png file (with alpha channel) using Media Library, my Wordpress installation makes all possible cropped versions loosing transparency.
This way, when I'm picking a perfectly transparent image for my site icon, I end up with favicons having ugly looking white background. To make things even worse, Wordpress' Media Library uses some weird size reduction algorithm, which causes my perfectly white / transparent background to be composite with all different shades of white / gray on all cropped images.
Is there any way to workaround this problem? Is this something in my configuration or is this another bug (loosing transparency / alpha channel when resizing image couldn't be a feature).
The only way I found to workaround this, is to download all cropped image files (after upload) through FTP, manually correct them (add transparency or fix background color) and re-upload them back, overwriting files generated by Wordpress. But, that sounds like a madness...