"For deletion prevention" is "짤방"(tchal-bang) in Korean.
The 짤방 (Jjal bang), it stands for 짤림 방지 (Jjalrimbangji). The 짤림 (Jjal rim) is word that means "Delete", and 방지 (Bangi) is word that means "prevention". When there is an image and it has a comment which is not related to that image, the image might be deleted. So, this word is the prevention of deletion of above situation.