Nexus-Gen: A Unified Multimodal AI Engine for Image Understanding, Generation, and Editing

What is Nexus-Gen?

Nexus-Gen is a unified multimodal generation framework that combines the natural language reasoning ability of LLMs with the visual creativity of diffusion models. It can simultaneously handle a wide range of tasks, including image understanding, image generation, and image editing.

Key Features

1. Image Understanding
Nexus-Gen can analyze and semantically interpret image content, identifying objects, scenes, or actions, and generating corresponding textual descriptions.

2. Image Generation
It supports generating high-quality images from textual or multimodal inputs. Nexus-Gen enables flexible and diverse visual content creation, suitable for creative design and other fields.

3. Image Editing
Nexus-Gen can perform local or global edits on existing images, including modifying elements, adding objects, or changing visual styles—ideal for tasks like image modification and style transfer.

Technical Principles

1. Dual-Phase Alignment Training
Nexus-Gen introduces a two-stage alignment strategy that bridges the gap between the output space of language models and the embedding space of image diffusion models.

Stage 1: Train the LLM to predict image embeddings under multimodal conditions.
Stage 2: Train a visual decoder to reconstruct high-fidelity images from the predicted embeddings.

2. Prefilled Autoregression Strategy
To address input mismatches between training and inference in autoregressive LLMs, Nexus-Gen proposes a prefilled autoregression method. Special padding tokens are added to explicitly mark image embedding positions, avoiding performance degradation due to distributional differences.

Project Links

GitHub Repository: https://github.com/modelscope/Nexus-Gen
Technical Paper (ArXiv): https://arxiv.org/abs/2504.21356

Application Scenarios

1. Multimodal Content Creation
Generate images from text and intelligently modify visual content. Ideal for advertising, social media content, AI-generated art, and more.

2. Intelligent Image Editing
Understand image semantics to support automatic retouching, inpainting, and style modifications, improving both speed and quality of image editing.

3. Education & Research
Nexus-Gen provides a unified platform for multimodal learning and cross-domain AI research. It is suitable for teaching, paper reproduction, and experimental validation.