[GRASSLIST:3790] Re: PNG driver

[SWlab]

> - vectors and the parts of rasters with black color are not drew on the PNG
> file

Likely to be a transparency problem: have you checked the values of 
GRASS_BACKGROUNDCOLOR and GRASS_TRANSPARENT ?

> - i can not set the width of the vectors.

I don't think you can change the width of vectors with d.vect in GRASS53. Try 
GRASS57, or use ps.map to get an EPS you can convert to PNG with gimp or 
Imagemagick