The most direct "free" way is through the official app. While the web version of Weidian is very limited, the mobile app (available on iOS and Android) has a built-in visual search engine.
Many high-quality sellers use "coded" names to avoid takedowns, making them impossible to find via text. weidian search image free
Instead of a live image search, use Ctrl+F on these spreadsheets to find the "Finds" or "QC" (Quality Control) photos shared by other users. Tips for Better Image Search Results The most direct "free" way is through the official app