problem with abr brushes help pls

[serizaeaaoi]

hi, i decided to use gimp for digital painting however when i import some abr brushes into gimp, they didn't behave 
like a brush at all. its like stamps forming a line 
myPaint brushes do behave like propper brushes but i can't find a way to convert my abr brushes into .myb brushes ( the format of mypaint brushes )
i can import them into png but that's it for now, i didn't find any way to convert them into myb

[rich2005]

New PS abr brushes have features that do not work with Gimp and The older .abr brushes are typically used as stamps. examples Grunge brushes, Cloud brushes, click as a stamp but not for click-n-drag.

Depending on the brush, in the brush tool options is a spacing value, sometimes you can get a better result by adjusting.

   

Converting to PS to MyPaint brush format ? I do know they are a png base but never seen one converted.