In short: LINE Creators Market checks every sticker image against a fixed canvas size and requires real transparency around the character — and a quick background-removal pass in a generic tool usually gets one of those two things wrong. RemoveGifBG's LINE preset (370×320) and a real per-pixel alpha channel fix both at once.
You've built a sticker set for LINE — individual character poses meant to be submitted through Creators Market. Each image needs to land on a specific canvas with the character cut out cleanly, and LINE's review process is unforgiving about it: mismatched dimensions or a background that isn't actually transparent are two of the most common rejection reasons creators run into.
RemoveGifBG includes a LINE Sticker preset (370×320, matching LINE's individual sticker canvas) in the output-dimensions dropdown, so you're exporting at the right size the first time instead of resizing a finished cutout. The alpha channel written out is real per-pixel transparency — it uploads as a clean cutout everywhere, not just in one tool's preview.
For a full set, batch multiple poses in one job and download them together, so every sticker in the set is cropped and centered the same way — which matters for how consistent the set looks once it's live.
What LINE Creators Market expects
See also: WeChat sticker guide · Telegram sticker guide