Transparent PNG

Hi,

up until yesterday (which happens to be when I upgraded WP), all the transparent PNGs I had uploaded were working fine. However, now, the PNGs that I uploaded before are still ok, but the new ones I have been trying to upload today are coming up flat.

When I upload them via the image widget, the come up in the preview as transparent first, but when I hit ‘save’ the preview changes to show a flat image.

Any ideas!

(to be honest, I don’t even know why I’m making PNGs, it was just the first file type I found through experimentation that let me save things transparently!)

Thanks

Victoria