I suggest you directly search and download transparent images on the internet.
There are a lot of free transparent HD image sites here.
Just use it after downloading.
Recommend some popular transparent image download sites:
https://www.freepik.com/free-photos-vectors/transparent
https://www.nicepng.com
https://www.clipartmax.com
But I need to remind you that if you use a copyrighted transparent image,
be sure to explain the source of the image to avoid unnecessary copyright troubles.