Many sticker sheets are exported on a white background. That is fine for previewing, but LINE needs transparency, otherwise every sticker shows up inside an ugly white box. The challenge is doing this without also deleting the white eyes, white text, or white highlights that are part of the artwork itself.
Why transparency matters
LINE composites stickers directly onto chat bubbles and backgrounds. A transparent PNG lets your character sit naturally in the conversation. A white rectangle behind it breaks the illusion and looks unprofessional — and LINE’s review may flag it.
The safe method: edge flood-fill
The reliable way to clear a background is edge-based flood-fill, not a blanket “make white transparent” filter:
- Start only from the outer border of the image.
- Remove pixels that are white (or near-white) and connected to that border.
- Stop at the first non-white pixel, so any white that is enclosed by the artwork is left alone.
This is exactly why a naive “select all white → delete” tool fails: it also deletes the white of a character’s eyes. Flood-fill from the edge respects the shape of your art.
Using the cutter’s background remover
In the HailouTec Sticker Cutter, after a sheet is split you can apply “remove white background” to any cell. It uses the edge flood-fill approach above, so:
- The surrounding white sheet vanishes to transparent.
- White inside the drawing (eyes, highlights, text) stays intact.
- The change is previewed per cell, so you can check before exporting.
When it still goes wrong
White that touches the border
If a white element in your art reaches the very edge of the canvas, the flood-fill may treat it as “background” and remove it. Fix: give the artwork a small transparent margin, or re-draw the edge so it is not pure white.
Off-white backgrounds
A “white” sheet is often #FCFCFC or #F8F8F8. A strict white-only removal leaves a faint haze. Use a tolerance setting (the tool’s threshold) so near-white is also cleared, but keep it tight enough not to eat light-gray art.
JPEG sources
JPEG introduces compression noise, so backgrounds are never a clean white. Convert to PNG first, or expect a slightly messy edge that you may need to touch up.
Best practice checklist
- Design on a transparent canvas from the start when you can.
- If you must start white, remove it with edge flood-fill, not global white-delete.
- Preview each cell; confirm interior whites survived.
- Export as PNG to keep the alpha channel.
Next: make sure the result matches LINE’s dimensions with the size & format guide →