There was a discussion in the chat about saving renders with transparent background with effects like bloom, emission glow, etc. which the glowing effect doesn’t saved along with the image. Just found a similar problem on Blender Artist forum: Blender 2.92 not saving alpha values properly - #10 by pitibonom - Compositing and Post Processing - Blender Artists Community
The solution was to also plug the image node to the alpha input of the output/composite (see first picture). The second pic is the saved result (PNG, RGBA). Last one is the result which imported into Gimp (I added black bg in Gimp to show the effect).
