Does the photo file required when applying for K-ETA have to be the same as the passport photo?

no. The photo file does not necessarily have to be the same as the passport photo, but must comply with the conditions below.
• Color photos
• JPG file
• Photo size is 20Mb or less.
• Hats, scarves, sunglasses, etc. cannot be worn.
• Clothing with colorful patterns is not permitted.
• At least 75% of the photos must be frontal, with your eyes open and looking directly at the camera.