How to change image resolution?
To specify image resolution use option "vdpi" (vertical DPI) and "hdpi" (horizontal DPI).
hdpi
Hdpi parameter specifies horizontal resolution of the resulting image. It can accept a positive number from 1 to 4096.
vdpi
Vdpi parameter specifies horizontal resolution of the resulting image. It can accept a positive number from 1 to 4096.
Example: