Credit line example: "Seoul-metro-234-4-Kkachisan-station-platform-20181121-105108.jpg from Wikimedia Commons by LERK, CC-BY-SA 4.0"A statement such as "From Wikimedia Commons" or similar is not by itself sufficient. If you do not provide clear attribution to the author and indicate the file name as shown here, you didn't comply with the terms of the file's license and may not use this file. If you are unable or unwilling to provide attribution and release your own work that incorporates this work with a Creative Commons Attribution-ShareAlike 4.0 license you should contact LERK to negotiate a different license. Informing me about usage is not mandatory, however, I'd appreciate a note if you use my work outside Wikimedia projects. Thanks! More of my work can be found in Category:Files by User:LERK.