Usually, people who draw pictures have copyright (China's copyright law stipulates that they can enjoy copyright without registration, and the time limit is 5 years before and after the author's death), but the pictures you downloaded from the Internet do not know the source and author, and if they are used for trademarks or other commercial purposes, they are likely to be infringed. Therefore, it is suggested that it is ok to refer to the creativity of offline pictures. If you want to use them, you'd better modify them before using them. If you can find the author, spend some money to buy it first, so as not to ask for a big price after the trademark becomes famous.