The LINE Home Cover size (1080×878px)
On LINE, the home cover is the large background image at the top of your profile's Home tab, and the recommended size is 1080x878 pixels, a nearly square but slightly landscape shape. This is the first thing friends see when they open your profile, sitting behind your profile photo and name, so it sets the tone for your whole page. Uploading at the native size keeps it crisp on the high-resolution phone screens where LINE is mostly used.
The layout consideration is the overlay. Your circular profile picture, display name, and status message sit on top of the lower portion of the cover, and the top of the image can be partly hidden behind the status bar and header controls. Because of this, the safest place for any focal point or subject is the upper-middle region, clear of the bottom where the profile block sits and clear of the very top edge, so the parts you care about are not covered by the interface.
Sizing to the native 1080x878 proportions avoids the awkward cropping and zoom that LINE applies when you upload an image of a very different shape into the cover slot. Since LINE profiles are personal and often decorative, a clean image that complements your profile photo rather than fighting it makes the page feel considered. This tool resizes 100% in your browser with no upload, it is free, and it preserves the aspect ratio. LINE occasionally revises its profile layout and cover dimensions, so verify the current size before you finalize your look.