Nano Banana 2 vs GPT Image 2.5

Specs side by side

Price per unit and per clip

Prices exclude taxes and are charged from your prepaid USD balance. Failed generations cost nothing.

In my tests the two models delivered very similar quality, and both handle in-image text reliably. Pick Nano Banana 2 when you want several variants per request, extreme formats (up to 8:1) or the shortest wait. Pick GPT Image 2.5 when cost matters and three sizes (up to 1536x1024) are enough, since every size and quality level costs the same.

Key differences

• Price. GPT Image 2.5 has one rate per image regardless of quality, size and references. Nano Banana 2 gets pricier with resolution (1K, 2K, 4K).
• Images per request. Nano Banana 2 returns up to 4, GPT Image 2.5 one.
• Size. Nano Banana 2: tiers from 0.5K to 4K and 14 ratios, including 1:8 and 8:1. GPT Image 2.5: three preset sizes (1024x1024, 1536x1024, 1024x1536) or auto; custom sizes are not available in Jantaris yet.
• References. Up to 14 in Nano Banana 2, 16 in GPT Image 2.5.
• Speed. In my tests on another provider Nano Banana 2 averaged 12.2 s per image, GPT Image 2.5 about 18 s at high and 38 s at max.

When to pick Nano Banana 2

• Four thumbnail variants for an A/B test in one run.
• Long 8:1 banners or 1:8 strips.
• Quick low-resolution drafts.
• When waiting time matters more than cost.

When to pick GPT Image 2.5

• A blog graphics series where price per image counts.
• A flat price per image, whatever the quality level.
• A 1024x1024 square, 1536x1024 landscape or 1024x1536 portrait at the same price.
• A project with 15-16 references.

Cost in practice

At 1K Nano Banana 2 costs about 1.6 times as much per image as GPT Image 2.5. GPT Image 2.5 has one price for each of its three sizes and tops out at 1536x1024, so the 2K and 4K tiers exist only in Nano Banana 2. For 4K from OpenAI, use GPT Image 2. With num_images: 4 in Nano Banana 2 you pay for each of the four images, and the 0.5K tier costs the same as 1K. Rates: from $0.07 per image (1K) and $0.0432 per image; all models on /pricing.

My tests on promptowy.com (Polish blog): Nano Banana 2 scored 8.6/10 in the image ranking, GPT Image 2.5 (Flare) 8.5 at high and 8.6 at max in a separate test on the same prompts. Both rendered an accented Polish sign without errors, and Nano Banana 2 also passed a harder typography test with a pangram. What to watch in Nano Banana 2: it adds content nobody asked for, and it drew pierogi that looked like gyoza. More: GPT Image 2.5 vs Nano Banana Pro vs FLUX.2.

FAQ

Nano Banana 2 or GPT Image 2.5: which is better?

Quality in my tests was practically equal. Price (GPT Image 2.5 is cheaper) and convenience (Nano Banana 2 is faster and gives 4 images at once) decide.

Which renders text better?

Both rendered an accented sign correctly. Nano Banana 2 also passed a harder pangram test without a letter error.

How much is a 4K image?

GPT Image 2.5 on Jantaris does not do 4K: it has three sizes (1024x1024, 1536x1024, 1024x1536), all at one price, $0.0432 per image. For 4K from OpenAI, use GPT Image 2. In Nano Banana 2 the 4K rate is clearly higher than 1K; see the model page.

Can GPT Image 2.5 return several images at once?

On Jantaris one request is one image, so several variants mean several tasks. In Nano Banana 2 set num_images up to 4.

Vendor examples

Official examples from the model vendors, not our generations.