Seedream 3.0

What it is

Seedream 3.0 is a Chinese–English bilingual image-generation foundation model from ByteDance Seed ^[1]. A foundation model, in this context, is a general-purpose generator trained at scale that later systems are built on top of. It takes a written prompt and returns an image; being bilingual means Chinese and English are both supported, including characters that appear inside the picture ^[1]. Its technical report was submitted to arXiv on 15 April 2025 by Yu Gao and 30 co-authors, and was revised to a third version on 28 June 2025 ^[1].

What changed from Seedream 2.0

The report frames Seedream 3.0 as an improvement on Seedream 2.0 in four areas: prompt alignment, rendering of complex Chinese characters, aesthetics and fidelity ^[1]. Prompt alignment is how closely the picture follows the instruction — whether the requested objects appear, in the right number and arrangement, in the style that was asked for. Rendering Chinese characters is a separate and harder problem: the writing system has many strokes per character and strict rules about how components are placed, so a model has to reproduce stroke shapes and relative positions, not just overall appearance. Aesthetics and fidelity cover the other half of the requirement — the image should look good and still stay faithful to what was described ^[1].

Training data and speed

Training data was doubled using a defect-aware training paradigm and a dual-axis data-sampling framework ^[1]. The first name points at training that takes account of defects in the data rather than assuming every sample is clean; the second concerns how examples are drawn during training, balanced along two axes at once rather than along a single dimension ^[1]. Alongside the quality work, the report describes a new acceleration approach that delivered a 4x to 8x speedup while keeping image quality ^[1]. Output is native high resolution, up to 2K ^[1]. Native here means the image is produced at that size rather than generated small and enlarged afterwards.

Where it sits

In September 2025 Seedream 3.0 was succeeded by Seedream 4.0, which unified generation and editing ^[2]. In 4.0, text-to-image synthesis, image editing and multi-image composition sit inside a single framework rather than in separate tools ^[2]. Its native output ranges from 1K to 4K, and it can produce a 2K image in up to 1.8 seconds without an LLM or VLM prompt-enhancement model ^[2]. That detail matters because many image pipelines first pass a short prompt through a language or vision-language model to expand it into a longer description; 4.0 does not need that step ^[2]. The Seedream 4.0 technical report was first submitted to arXiv on 24 September 2025 ^[2].

Read together, the two reports trace a short arc. Seedream 3.0 is about doing single-image generation better: following prompts more closely, getting Chinese characters right, raising resolution and cutting the time needed for one image ^[1]. Seedream 4.0 is about folding generation and editing into one system ^[2].