Seedream 4.5 and GPT-5.2 Pro are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Seedream 4.5, from bytedance-seed, has a 4,096-token context window and is priced at $0.04/image on OpenRouter.
GPT-5.2 Pro, from OpenAI, has a 400,000-token context window and is priced at $21/M tokens input, $168/M tokens output on OpenRouter.