Use a prompt that asks for a PNG with real transparency , not just a picture that looks transparent.

Prompt you can copy

Create a clean cutout of [your subject] on a fully transparent background.
Return the final image as a real PNG file with an alpha channel.
Do not add a white background, checkerboard background, watermark, border, or extra elements.
Keep the subject centered and isolated.

Stronger version

Make a transparent PNG of [your subject].
The background must be truly transparent, not fake transparency or a checkerboard pattern.
Output only the final PNG file.
Do not generate your own background, extra objects, text, shadows, or frame.

If it still adds a background

Try adding:

  • “Use alpha transparency.”
  • “No background at all.”
  • “No checkerboard.”
  • “No watermark.”
  • “Output only the image file.”

Best practical trick

If the model still refuses, ask for:

a subject on a solid pure white background, then remove the background afterward

That often works better than hoping the model makes a perfect transparent file directly. The current public guidance and forum examples suggest that asking explicitly for a PNG with real alpha transparency and no background is the key, while some workflows still fail unless transparency is handled as a separate step.

Short version

“Create a transparent PNG with real alpha channel, no background, no checkerboard, no watermark, and output only the final file.”