PNG Transparent Cloud Files Library

I learn from one of the video, Create custom smoke/cloud brush with GIMP
and i stop at half the video as i dont need brush.
So first step is take photo which i got alot of cloud photos
Then you desaturate
Then you level it by pulling the first input level bar triangle button under the chart.
Pull untill you see black color in back ground pitch black.
Then you invert it
Then you copy visible which save alot of time instead of pixell by line cut out
Then add new layer paint it black
Add layer mask black Full transparent
Do the paste command
invert the paste
Merge Down
Delete original
Apply layer mask.

This is his part where i stop the rest of making brush
Now my part

You invert it back to white
As it is very invisible so you duplicate it few times
Merge all together and got the normal cloud.

Then i add a little different each cloud i make i create smaller size

After each small and big different
I add another step
which is each picture adjust exposure to max -1.2

This create another set of picture at lower exposure.