Seedream 5.5 vs Nano Banana Pro: 5 Tests, Price & Speed

ByteDance released Seedream 5.5 on November 9, 2026, and the first question most people ask is whether it can replace Nano Banana Pro, Google's go-to model for realistic images and edits. We gave both models the same five prompts on ImagesArt, at the same size and aspect ratio, and put the results side by side.

Short answer: Seedream 5.5 won 3 of 5 rounds. Pick it for posters, transparent PNGs and edits you keep changing over several rounds; it was also faster in six of seven runs (the seventh was a tie) and costs 4 credits at 1K instead of 8. Pick Nano Banana Pro for realistic portraits with exact text and for one-shot product edits where the camera angle must not move.

Try Seedream 5.5 →

Seedream 5.5 vs Nano Banana Pro at a glance

Render times run from pressing Create to the finished image on our site. Over the last 30 days, the median finished job on ImagesArt took 21 seconds on Seedream 5.5 and 41 seconds on Nano Banana Pro, so the gap is not a fluke of our test day. The Seedream images were made on our Seedream 5.5 page on November 13 and 14; the Nano Banana Pro images in our image generator on November 15, with the same prompts and settings.

Test 1: realistic portrait with a chalkboard

Text to image, 3:4, 2K:

Cinematic close-up portrait of a 30-year-old woman with freckles and loose auburn hair, sitting by a rain-streaked café window at dusk, warm tungsten light on her face, neon reflections in the glass, natural skin texture with visible pores, 85mm lens, shallow depth of field. A small chalkboard behind her reads "Open Late · Fresh Pastries" in neat handwriting, and that is the only text on it.

Both got the chalkboard line right and both look like photos, not renders. Seedream 5.5 has the softer, more natural mood and the woman looks closer to 30. But it ignored "that is the only text on it": there is an extra line of made-up handwriting at the top of the board. Nano Banana Pro kept the board clean and its skin detail, pores and freckles hold up even when you zoom in.

This round: Nano Banana Pro.

Test 2: event poster with English and Japanese text

Text to image, 16:9, 2K:

A clean modern event poster for a fictional night market called "Lantern Street Market". Warm paper lanterns hang over a street of food stalls at blue hour. Large headline "LANTERN STREET MARKET" at the top, with the Japanese line "ちょうちん横丁ナイトマーケット" beneath it. Small info text at the bottom reads "Fri–Sun · 6 PM – Midnight · 120 Food Stalls · Free Entry". Crisp editorial layout, readable typography, rich warm light.

Both models spelled all three lines correctly, including the Japanese line and the small info text. The difference is the layout. Seedream 5.5 used the whole wide frame as the poster, with real Japanese signs on the stalls. Nano Banana Pro drew a portrait poster card in the middle and filled the rest of the 16:9 frame with blur, so you would have to crop it before using it as a banner. Seedream did add a few short lines we did not ask for, such as "A brighter night together", so read your poster before you print it.

This round: Seedream 5.5.

Test 3: sticker on a transparent background

Text to image, 1:1, 1K:

A cute die-cut sticker of a smiling cartoon avocado wearing tiny sunglasses and holding a surfboard, bold clean outlines, vibrant flat colors, with the words "Stay Chill" in rounded bubble letters under it.

On Seedream 5.5 we turned on Background: Transparent. Nano Banana Pro has no such setting, so we added "On a transparent background." to its prompt.

This is the clearest gap in the test. Seedream 5.5 returned a PNG with a real alpha channel: about 59% of the pixels are fully see-through, so you can drop the sticker on any color. Nano Banana Pro returned a JPG with a grey checkerboard painted into the picture. It looks transparent on screen, but the "background" is pixels, and you would still need a background remover.

This round: Seedream 5.5.

Test 4: edit a product photo

Image to image, one reference photo, 4:3, 2K. This is the photo both models got:

Keep the canister, its label text and the camera angle exactly the same. Change only the setting: place it on a dark walnut table in a cozy morning kitchen with soft steam rising from a cup of coffee beside it.

Both kept the label word for word, including the small "Single Origin · Ethiopia" line. Nano Banana Pro also kept the camera angle and the coffee beans from the original. Seedream 5.5 pulled the camera back and up a little and dropped the beans, so the shot no longer matches the original framing.

This round: Nano Banana Pro.

Test 5: three edits in a row

Seedream 5.5's headline feature is editing the same picture again and again without it slowly falling apart. We started from the same canister photo and fed each result back in as the next input, at 4:3 and 1K:

1. "Keep the canister, its label text and the camera angle exactly the same. Change only the setting: place it on a white marble kitchen counter in a bright minimalist kitchen."
2. "Keep everything in the scene exactly the same: the canister, its label, the coffee beans and the camera angle. Change only the lighting: warm golden-hour sunlight streaming in from the left window, with long soft shadows across the marble."
3. "Keep everything exactly the same: the canister, its label, the coffee beans, the camera angle and the golden-hour light. Add only two props on the counter: a white ceramic cup of latte with heart latte art to the right of the canister, and a small linen napkin under the cup."

Seedream 5.5, rounds 1–3 · 23 s, 21 s, 15 s · 6 credits each

Nano Banana Pro, rounds 1–3 · 34 s, 31 s, 31 s · 8 credits each

After three rounds, both still had the right label and the same canister. The difference is image quality. Each Nano Banana Pro round came back a little softer and more yellow: by round 3 the whole picture has a haze and the small "Single Origin · Ethiopia" line is fading into the jar. Seedream 5.5 stayed sharp all the way through. Its only slip was placing the latte cup so it covers the end of the small label line.

Three rounds is a short run. ByteDance says Seedream 5.5 holds up over far more edits than that; we have not tested 10 or more yet.

This round: Seedream 5.5.

What it costs

On ImagesArt you pay per image with credits:

• Seedream 5.5: 4 credits at 1K, 7 at 2K, plus 2 for each reference photo. A transparent PNG costs the same as a normal image. Free accounts can use 1K.
• Nano Banana Pro: 8 credits at 1K or 2K, 14 at 4K. Reference photos do not cost extra. It is only on paid plans.

So a plain 1K image costs half as much on Seedream 5.5. For an edit with one photo at 2K the two are close: 9 credits on Seedream 5.5 against 8 on Nano Banana Pro. Credits are only used when an image comes out.

Which one should you use?

• Seedream 5.5 for posters and banners with text, stickers, logos and product cutouts that need a transparent PNG, and edits you plan to keep changing over several rounds. It is also the one to use when you are still trying prompts, since it was faster in six of our seven runs and tied on the seventh.
• Nano Banana Pro for realistic portraits where the text in the scene has to be exactly what you wrote, for single product edits where the framing must not move, and for anything you need at 4K.

Try both on ImagesArt

Seedream 5.5 has its own page with text to image, image to image, the Transparent background setting and a Layers tab that splits one photo into separate PNG layers. Nano Banana Pro is in the model list of our AI Image Generator, so you can paste the same prompt into both and compare.

Open the Seedream 5.5 generator →

Related reading

Want to see how Seedream 5.5 does against OpenAI's newest model? Read Seedream 5.5 vs GPT Image 2.6, where we ran the same five tests.

FAQ

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