Two image generation models are dominating 2026: OpenAI's gpt-image-2 and Google's Nano Banana Pro (Gemini 3 Pro Image). Both produce stunning results, but they have fundamentally different strengths. We compared them specifically for generating AI companion character art.

The Contenders

GPT Image 2 (April 2026): Native reasoning, 2K resolution, multi-image consistency, #1 on Image Arena with a 242-point lead. Costs ~$0.08-0.17/image.

Nano Banana Pro (March 2026): 4K native output, 94-96% text rendering accuracy, strong character consistency, API-first design. Costs ~$0.05-0.24/image depending on resolution.

Head-to-Head: Character Art

Anime-style characters

Winner: Nano Banana Pro. Google's model produces cleaner anime linework and more consistent proportions. GPT Image 2 tends to add a slight "painterly" quality to anime that some users love and others find distracting. Nano Banana keeps the flat color and sharp lines that anime fans expect.

Realistic portraits

Winner: GPT Image 2. The reasoning capability shows here — GPT Image 2 produces more natural skin textures, lighting, and facial expressions. Nano Banana Pro's realistic portraits are good but occasionally have a "too perfect" quality that dips into uncanny valley.

Character consistency across images

Winner: GPT Image 2. The multi-image consistency feature is purpose-built for this. You can generate the same character in 5 different scenes and she looks recognizably the same. Nano Banana Pro requires more careful prompting to maintain consistency.

Resolution and detail

Winner: Nano Banana Pro. Native 4K output means more detail in hair, clothing textures, and accessories. GPT Image 2 maxes out at 2K.

Cost efficiency

Winner: Nano Banana Pro. At $0.05/image for standard resolution, it's significantly cheaper for bulk generation. GPT Image 2's reasoning mode takes longer and costs more per image.

Our Recommendation

Use GPT Image 2 when you need character consistency across multiple images (profile pics, scene illustrations) or realistic portraits. Use Nano Banana Pro for anime-style art, bulk generation, or when you need maximum resolution. Many creators use both — Nano Banana for initial exploration, GPT Image 2 for final polished versions.

Sources

How to Judge an Image Model for Companions

Do not judge these models only by their best gallery image. Test them like a product: generate the same character smiling, annoyed, sleepy, outdoors, in a different outfit, in anime style, in realistic style, and in a cropped profile avatar. The model that wins is the one that keeps identity stable while still allowing expression and scene variety.

Cost changes behavior too. If one model is twice as expensive, users hesitate to regenerate, which makes character creation feel brittle. A slightly weaker model with cheaper iterations can produce better final results because users can explore more variations before settling on the version they actually want.