ZDoom

(Image)RGB=>
(Layers)Layer from Background=>
(Image)Adjustments>Brightness\Contrast(Auto)=> //This action is optional adn individual for each image
(Image)Adjustments>Brightness\Contrast(Auto)=> //This action is optional adn individual for each image
(Image)Adjustments>Color Balance(+40 Blue)=> //This action is optional adn individual for each image
(Channels)Load channel as selection=>
ПКМ=>Select Inverse=>Delete

Problem was solved, at last!

To smooth deletening background is better to use alpha-channels selection inverting. I use Photosho CS6 with next actions:

[code](Image)RGB=>
(Layers)Layer from Background=>
(Image)Adjustments>Brightness\Contrast(Auto)=> //This action is optional adn individual for each image
(Image)Adjustments>Brightness\Contrast(Auto)=> //This action is optional adn individual for each image
(Image)Adjustments>Color Balance(+40 Blue)=> //This action is optional adn individual for each image
(Channels)Load channel as selection=>
ПКМ=>Select Inverse=>Delete[/code]

Result is:
[url=https://postimg.cc/image/v9lce6qhf/][img]https://s5.postimg.cc/v9lce6qhf/_Common_Glow_Original_50x50_grey_grid.jpg[/img][/url]
Oh, just important note: an effect must be edited separately from other image objects (diablo body in my case).

RenderStyle Add
Alpha [i]value[/i]

Like as Sandro (TS) had [url=https://forum.zdoom.org/viewtopic.php?f=3&t=48708&p=837666&hilit=aura#p837574]shows in his own thread[/url]:
[img]http://i.imgur.com/rR55sXZ.png[/img]

I have the similar problem with sprites transferring, but even bit complicated probably.
[spoiler]Whenever I shall prepare sprites in specific editor for transferring, all are looks perfect as I needed:
[url=https://postimg.cc/image/qirrb5i77/][img]https://s5.postimg.cc/qirrb5i77/1_Editing.jpg[/img][/url]

but then I had been forced to choose background colour for saving image, whIch is still looks good at this step:
[url=https://postimg.cc/image/wwgueefdf/][img]https://s5.postimg.cc/wwgueefdf/2_Editing.jpg[/img][/url]

and finally, when I do image conversion in Slade, I get those awful non-transparent borders which are remains from background adding:
[url=https://postimg.cc/image/6pfnhuwxf/][img]https://s5.postimg.cc/6pfnhuwxf/3_Editing.jpg[/img][/url]

In the game it looks even much worse:
[url=https://postimg.cc/image/3vci4mctf/][img]https://s5.postimg.cc/3vci4mctf/Diablo_Non_Transparent_Effect.jpg[/img][/url][/spoiler][spoiler=Animated examples][url=https://postimages.org/][img]https://s5.postimg.cc/w87zuvo7b/HPSC_new.gif[/img][/url][url=https://postimages.org/][img]https://s5.postimg.cc/fkghsfbg7/HPSC.gif[/img][/url][/spoiler]And moreover, all should be ok since the DECORATE allows to assign for actor a some specific properties like as:
[code]RenderStyle Add
Alpha [i]value[/i][/code]but it will force to render whole sprite, not only effect.

And like as Sandro had wrote: "I expect this to be a novice mistake, but I would be grateful if someone could provide a solution."
P. S. Since that matter is very important for my work, so your advice will be welcomed in anytime, unless it will be solved or closed.