In-Depth Comparison of Image Generation: Gemini vs ChatGPT

Comparison of Image Generation: Gemini vs ChatGPT

Introduction

A recent study conducted by Combeez Inc. delved into the image generation abilities of two leading AI models: Google’s Gemini 3.5 Flash and OpenAI’s GPT-5.5 Instant. This report summarizes their performance and character fidelity, specifically focusing on an original character named Konbi-chan.

Research Overview

The study involved testing both AI systems using two distinct prompt categories: simple and complex. The evaluations aimed to assess each AI's capacity to accurately generate character images based on varying levels of detail.

Research Phase 1: Basic Instruction Comparison

The initial phase focused on simpler prompts. For this experiment, the command was:

"Generate an illustration of the attached character flying in a city."

Both Gemini and GPT were able to interpret this straightforward instruction effectively, producing satisfying results with a character soaring through cityscapes. The ability to handle uncomplicated prompts indicates that both AIs possess a high degree of practicality in these scenarios.

Research Phase 2: Complex Instruction Comparison

The second phase involved a significantly more intricate prompt to challenge both models:

"Create a vertical wallpaper (aspect ratio 9:16) in a vibrant watercolor style with soft touches. The background should feature a sunflower field glowing under the strong summer sun, with a bright blue sky and fluffy white cumulonimbus clouds in the distance. Centrally positioned should be the attached bee character, which has a bright yellow umbrella floating above it, mimicking a sunshade. Both the character and the umbrella should be in a similar miniature size. The image should be filled with sparkling summer light, embodying an open and refreshing summer scene."

The results from this phase highlighted the strengths and weaknesses of each AI. GPT emerged as the superior performer in terms of overall quality and character fidelity, accurately capturing details and nuances from the complex prompts.

Conversely, while Gemini showcased warm and storybook-like illustrations, it struggled to fully capture the intricacies of the given instructions (e.g., mistakenly adding limbs to the character).

Conclusion and Future Outlook

The findings suggest that, at present, GPT possesses a notable advantage in performing detailed character illustrations and complex compositions, demonstrated through this study. However, it's vital to note that AI technology continuously evolves, with regular updates enhancing capabilities and output quality.

Moving forward, both models may improve, leading to exciting advancements in the field. Combeez Inc. aims to continue presenting valuable research findings regarding AI techniques and efficiencies. Don’t forget to check out our proprietary prompts to enhance your efficiency:

Study Details

- Research Focus: Comparison of image generation and character representation abilities in leading AIs (Gemini 3.5 Flash / GPT-5.5 Instant)
- Study Duration: April 17, 2026, to May 16, 2026
- Objective: To investigate the output results based on the complexity of AI prompts and identify the strengths and weaknesses of each model.

Disclaimer: This article is based on internal comparative research by Combeez Inc. The results reflect performance under specified conditions and may not guarantee similar outcomes across all characters and image generation tasks.