Seedream 5.5 vs GPT Image 2.6 Sunburst: which should you choose?

A finished product ad needs two changes: turn the red mug cobalt blue and replace its price label. The logo, shadows, layout, and everything else must stay put.

If editing preference is your priority, GPT Image 2.6 Sunburst (max) has the stronger published result. GPT is also the first candidate for schema-documented region controls. Put Seedream 5.5 on the shortlist when successive natural-language revisions are the requirement: ByteDance's editing-preservation demonstration makes it relevant, not a proven winner.

No primary comparative test reviewed settles this exact mug-and-price-label job. This is a sourced selection guide, not our measured comparison; no generation requests were run. The AIHubMix comparison page provides model navigation, not proof of a task winner or an equal-setting cost advantage.

Define what must survive the edit

Use a 2048×2048 source PNG you own. Ask for the mug-color and price-text changes together, then judge the result against explicit acceptance checks:

• The mug becomes cobalt blue without changing its geometry or material appearance.
• The label reads exactly US$19.99, retaining its position and shape.
• The logo, other text, shadows, props, background, and crop remain unchanged; inspect at full resolution.
• If successive revisions matter, compare each accepted intermediate image with the original, not just the previous result.

These are proposed checks, not measured outcomes. A plausible-looking image can still fail an ad's exact-text or brand-preservation requirement.

Editing preference is not 100-round durability

ByteDance's launch post, dated November 9, 2026, demonstrates 100 successive edits and claims better preservation outside edited areas. That is vendor evidence, not an independent reproduction. Its named external comparators are GPT Image 2.5 Sunburst and Nano Banana 2.1—not GPT Image 2.6 Sunburst.

For independent editing evidence, Artificial Analysis's AA-Image-Editing v2.1 leaderboard uses blind human pairwise preferences between outputs made from the same source image and instruction.

UTC snapshot: 2026-11-12 06:24:03. These are the displayed overall editing rows, with their exact variant labels:

This gives the named GPT (max) variant the higher general editing preference score in this snapshot. It does not establish the success rate for the mug and label, or which model preserves a composition through 100 revisions. We do not infer statistical significance from these confidence intervals alone.

Nor should a default setting—or the high example below—inherit the benchmark's (max) result.

Compare the controls on the route you will use

The current Seedream gateway schema and GPT gateway schema, inspected November 12, 2026, document this distinction for POST /ai/v1/images/generations:

For GPT, top-level quality lists low, medium, high, xhigh, max, and auto. extra.quality is deprecated and overridden by the top-level field. Separate complexity lists low, medium, and high. The schema notes that allowed values depend on the model; acceptance of every listed value was not verified here.

GPT's markup is a transparent PNG annotation layer matching the first source image's dimensions; it cannot be combined with mask. These are published schema controls, not tested enforcement or fidelity guarantees. A mask should not be treated as proof that every unselected pixel will survive unchanged.

Seedream exposes none of those selectors, nor layer_decomposition, on this route. That is a gateway-contract distinction, not proof of a model-level inability. Do not assume unsupported fields pass through.

ByteDance also describes native full and partial transparency. That does not promise transparent Seedream output through this gateway: PNG alone proves nothing about alpha. GPT's schema documents extra.background="transparent" with PNG or WebP. If alpha is mandatory, inspect the returned file's alpha channel on the actual route; neither model's output was verified here.

Price tokens, not an assumed finished image

OpenAI's model page lists these official GPT Image 2.6 Sunburst rates in USD per million tokens: $5 text input, $8 image input, and $30 image output. It does not give this model a fixed per-image price.

For those three uncached categories:

USD = (5 × text_input_tokens
     + 8 × image_input_tokens
     + 30 × image_output_tokens) / 1,000,000

Hypothetical, not measured: assume 1,000 text-input tokens, 1,000 uncached image-input tokens, and 2,000 image-output tokens for one edit. The calculation is $0.005 + $0.008 + $0.060 = $0.073.

Those counts do not describe a particular resolution, high, or AA's max configuration. The example uses uncached official token rates, excludes retries, and is neither an AIHubMix quote nor a measured bill.

A complete official Seedream 5.5 rate table was not found in the official material reviewed. There is no defensible equal-setting cost winner here, and no supported savings ratio. For procurement, compare the cost of accepted edits—including retries—only after quality requirements and actual usage are known.

Two starting requests, not a benchmark

The unified image API guide documents reference-image inputs and the shared endpoint. Both requests below use the same local PNG, prompt, n=1, dimensions, and output format. GPT additionally sets top-level quality="high"; Seedream has no matching selector. Equal dimensions are not equal compute effort, and this does not reproduce AA's (max) result.

Use Bash with curl, jq, and base64; set AIHUBMIX_API_KEY in your environment and place your owned source at ./source-ad.png. Running these examples submits billable requests. They have not been executed for this article.

set -euo pipefail
: "${AIHUBMIX_API_KEY:?Set AIHUBMIX_API_KEY first}"
SOURCE_IMAGE="./source-ad.png"
test -r "$SOURCE_IMAGE"
SOURCE_DATA_URI="data:image/png;base64,$(base64 < "$SOURCE_IMAGE" | tr -d '\r\n')"
PROMPT='Change only the red mug to cobalt blue and replace the price label text with exactly "US$19.99". Preserve the label position and shape, logo, shadows, other objects, background, framing, and all other text.'

# Seedream 5.5: no quality field on this route.
printf '%s' "$SOURCE_DATA_URI" |
  jq -Rs --arg prompt "$PROMPT" '{
    model: "doubao-seedream-5-5", prompt: $prompt, image: .,
    n: 1, size: "2048x2048", output_format: "png",
    extra: {watermark: false}
  }' |
  curl --fail-with-body --silent --show-error \
    https://aihubmix.com/ai/v1/images/generations \
    -H "Authorization: Bearer $AIHUBMIX_API_KEY" \
    -H "Content-Type: application/json" --data-binary @-

# GPT Image 2.6 Sunburst: high is not the leaderboard's max.
printf '%s' "$SOURCE_DATA_URI" |
  jq -Rs --arg prompt "$PROMPT" '{
    model: "gpt-image-2.6-sunburst", prompt: $prompt, image: .,
    n: 1, size: "2048x2048", output_format: "png", quality: "high"
  }' |
  curl --fail-with-body --silent --show-error \
    https://aihubmix.com/ai/v1/images/generations \
    -H "Authorization: Bearer $AIHUBMIX_API_KEY" \
    -H "Content-Type: application/json" --data-binary @-

Seedream's schema declares a visible-watermark default of true. Its request above sets extra.watermark=false to request omission of that mark; this behavior has not been output-tested.

Both schemas permit optional asynchronous execution. Check account-level task-feature activation before using native task APIs; 403 async_not_enabled means activation is required. Download a returned content_url with the same API key/Bearer token that created the task; it is not a public reference-image URL. For another revision, download the accepted image and build a new data URI rather than treating that protected URL as public input.

Choose by the requirement that can disqualify a result

Choose GPT as the first candidate when explicit region guidance or the published editing preference signal matters most. Evaluate Seedream when the workflow genuinely depends on successive natural-language revisions, without promoting its vendor demonstration into comparative proof.

For this ad, approve neither on ranking alone. Check the mug, label, and protected regions. If exact label text remains unacceptable, keep the price label as an editable design element rather than accepting a visually convincing mistake.

FAQ

Which model is better for changing a mug and a price label?
No primary comparative test reviewed settles that exact task. GPT has the higher published editing score for its max variant; Seedream's successive-edit demonstration is a reason to evaluate it, not a task win.

Does Seedream's 100-round demonstration prove it beats GPT Image 2.6?
No. It is vendor evidence, not an independent 100-round comparison with GPT Image 2.6. The launch post names GPT Image 2.5 Sunburst among its comparators.

Can both accept a reference image through AIHubMix?
Their current unified schemas document image and images inputs. The examples share one source image, but no output was generated or checked here.

Can GPT use mask and markup together?
No. Its published schema lists both but makes them mutually exclusive. Markup must match the first source image's dimensions; listing the controls does not guarantee preservation.

Should GPT quality go inside extra?
Use top-level quality. The compatibility field extra.quality is deprecated and overridden by it. The example's high setting is not the benchmark's max variant.

Does PNG guarantee a transparent Seedream asset?
No. Native transparency is a vendor claim, while this gateway schema exposes no background selector for Seedream. GPT documents a transparent-background selector, but actual alpha output still needs inspection.

Which is cheaper per accepted edit?
This guide cannot establish that. The $0.073 GPT example uses hypothetical token counts, not measured usage; no comparable complete official Seedream rate table was found in the material reviewed.

Keep reading: the Seedream 5.5 series

• Deciding whether to replace an existing Seedream workflow? Read Seedream 5.5 vs 5.0 Pro: is it worth upgrading?.
• Need generation, editing, and migration details before integrating either option? Read Seedream 5.5 API tutorial: generation, edits, and migration.

Sources

1. ByteDance Seed: Introducing Seedream 5.5.
2. Artificial Analysis: AA-Image-Editing v2.1 leaderboard, snapshot 2026-11-12 06:24:03 UTC.
3. OpenAI: GPT Image 2.6 Sunburst model page and official pricing.
4. AIHubMix: current Seedream 5.5 endpoint schema.
5. AIHubMix: current GPT Image 2.6 Sunburst endpoint schema.