Can a JPG be transparent? No: make a transparent PNG instead

No: a JPG (JPEG) can't be transparent. The format stores a color for every pixel but has no alpha channel, the per-pixel opacity that transparency needs, so every pixel is opaque and any see-through area is saved as a solid color. That is why a JPG logo shows a box around it on a colored page. To get a transparent background, cut the subject out and save it as a PNG, which can store an alpha channel. Sume's background removal does this from a URL: send your JPG's public HTTPS address to POST /v1/rmbg-1.0/remove and you get back a PNG with alpha.

The file-format facts are general. The Sume steps come from the RMBG 1.0 schema in the OpenAPI document behind the Sume API reference, plus Sume's Image API and Media inputs docs, read on 2026-09-28.

Why can't a JPG store transparency?

An image file stores red, green and blue values for each pixel. Formats that support transparency add a fourth value, alpha, which says how opaque the pixel is, from fully see-through to solid. JPEG has no slot for that fourth value. PNG and WebP do, and GIF can mark one color as fully transparent.

A JPG that shows a gray-and-white checkerboard behind the subject isn't transparent either: that checkerboard is painted into the pixels, part of the picture like everything else.

How do I turn a JPG into a transparent PNG?

Renaming logo.jpg to logo.png changes only the name, and re-saving it as a PNG changes the file type but not the pixels: the background is still there, now opaque inside a PNG. The background has to be removed. With Sume:

• Put the JPG at a public HTTPS URL. Localhost, private-network and non-HTTPS URLs are rejected before the job is submitted.
• Send it as image_url to POST /v1/rmbg-1.0/remove. That is the only required field; Sume picks the model, and model ids are not accepted.
• The job runs async by default. Poll its status until it is completed, failed or canceled; a completed job's result holds PNG artifacts with alpha, mirrored to Sume.
• Keep the result as a PNG. Saving it as a JPG again fills the transparent area with a solid color.

curl -X POST https://api.sume.com/v1/rmbg-1.0/remove \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "image_url": "https://example.com/logo.jpg" }'

curl https://api.sume.com/v1/jobs/job_123/status \
  -H "Authorization: Bearer $SUME_API_KEY"

curl https://api.sume.com/v1/jobs/job_123/result \
  -H "Authorization: Bearer $SUME_API_KEY"

Does background removal just make the white parts transparent?

No. It separates the subject from its background; you don't pick a color to remove, and the request has no color or tolerance field. So check white or light parts inside the subject, such as lettering in a logo, at full size after the cutout. For making a brand-new graphic that ends up transparent, see AI image generator with a transparent background.

PNG vs JPG vs WebP: which one keeps transparency?

PNG and WebP can hold transparency; JPG can't. On Sume, the background-removal cutout is the output that carries alpha, and it comes back as a PNG.

What does the cutout cost, and what are its limits?

API pricing lists background removal at $0.0225 per image, plus a 5.5% agent fee by default, and the price does not vary by image size. Remove background API covers the call's other fields, wait modes and webhooks.

• One image per job: image_url is a single URL. Remove background from images in bulk covers running many.
• No output format option: the result is a PNG with alpha.