The import feature is for import DragonBones Data including xml, json, data merged png, and so on. If you want to import png as a asset, please click import button in Library panel, or just drag the png into the DBPro.
The English version User Guide and API are mading by one of our team member. It still need some time to finish all of them.
Vector element are not supported, and we still have no plan to support Vector element. But technically because we used Flash AIR to implement the Editor, so supporting vector element will not be a hard thing for us.
May I know, why you have the requirement? What is expected workflow? Design assets in AI and import to DBPro to design animations? Does anyone else have this requirement? You guys can VOTE here, and we can decide the priority of this task 😛