Styles and Quality Modifiers

Welcome back! In the previous lesson, you learned how to craft effective prompts by focusing on the key components: subject, context, and style. This lesson builds on that foundation by introducing you to styles and quality modifiers, which are essential for enhancing the quality and artistic expression of your generated images.

By the end of this lesson, you will understand how to combine these elements to create visually stunning and high-quality images using Google's Gemini API and its gemini-3.1-flash-image model.

Quality modifiers are keywords that enhance the detail and clarity of generated images. They help the model understand that you are aiming for a high-quality asset. For instance, general modifiers like high-quality, beautiful, and stylized can be used to improve the overall aesthetic of an image.

When generating photos, you might use specific modifiers such as 4K, HDR, or Studio Photo to achieve a more realistic and detailed output. Similarly, for art and illustration, modifiers like by a professional or detailed can add depth and intricacy to the artwork.

To illustrate the impact of quality modifiers, consider the following example. A prompt without quality modifiers, such as a photo of a corn stalk, might produce a basic image. However, by adding quality modifiers like 4K HDR beautiful photo of a corn stalk taken by a professional photographer, the resulting image will be more vibrant and detailed.

Artistic styles define the visual approach of a generated image. In this lesson, we will explore two main styles: photography and art/illustration. For photography, you can use prompts that start with A photo of... to generate photorealistic images. For example, A photo of coffee beans in a kitchen on a wooden surface will produce an image that resembles a real photograph.

In contrast, art and illustration styles allow for more creative expression. You can use prompts like A painting of... or A sketch of... to create images in various artistic styles. For instance, A technical pencil drawing of an angular sporty electric sedan with skyscrapers in the background will generate a detailed pencil sketch, while A digital art of an angular sporty electric sedan with skyscrapers in the background will produce a vibrant digital artwork.

Let's dive into a code example to see how you can combine artistic styles with quality modifiers to generate high-quality images. The following code snippet is written in PHP using the Guzzle library for making HTTP requests.

<?php

require 'vendor/autoload.php';

use GuzzleHttp\Client;
use GuzzleHttp\Exception\RequestException;

// Load API key from environment
$apiKey = getenv("GEMINI_API_KEY");
if (!$apiKey) {
    die("GEMINI_API_KEY environment variable not set.\n");
}

// Define endpoint
$endpoint = getenv("GEMINI_BASE_URL") . "?key=" . $apiKey;

// Define prompts combining artistic styles with quality modifiers
$styleQualityPrompts = [
    "A beautiful landscape, photorealistic style, 4K resolution",
    "A portrait of a woman, oil painting style, high definition",
    "A futuristic cityscape, cyberpunk style, ultra-realistic, 8K resolution",
    "A serene beach scene, watercolor painting, high-quality details",
];

// Initialize HTTP client
$client = new Client();

foreach ($styleQualityPrompts as $prompt) {
    $payload = [
        "contents" => [
            [
                "parts" => [
                    ["text" => $prompt]
                ]
            ]
        ],
        "generationConfig" => [
            "responseModalities" => ["TEXT", "IMAGE"]
        ]
    ];

    try {
        $response = $client->post($endpoint, [
            'headers' => [
                'Content-Type' => 'application/json'
            ],
            'json' => $payload
        ]);

        $body = json_decode($response->getBody(), true);

        // Extract image data from the response
        $parts = $body['candidates'][0]['content']['parts'] ?? [];
        foreach ($parts as $part) {
            if (isset($part['inlineData'])) {
                $imageData = base64_decode($part['inlineData']['data']);
                // Save the generated images in the app/public/images directory
            }
        }

    } catch (RequestException $e) {
      // Exception handling ...
    }
}
?>

In this example, we define a list of prompts that combine artistic styles with quality modifiers. Each prompt specifies a style, such as photorealistic or oil painting, along with quality modifiers like 4K resolution or high definition. The code then generates an image for each prompt using the Gemini API.

The request body uses a contents array with parts containing the prompt text, and generationConfig instructs the model to return an image. The response image data is found under candidates -> content -> parts -> inlineData, where it is base64-encoded and ready to be decoded and saved to the specified directory.

The image below demonstrates the result of using a prompt that combines a mountain landscape with an oil painting style. Notice how the AI incorporates the texture and brushwork characteristic of an oil painting while maintaining high visual fidelity.

In this lesson, you learned how to enhance your image generation by combining styles and quality modifiers. We explored the impact of quality modifiers on image detail and clarity, and how different artistic styles can influence the visual output. By understanding and applying these concepts with the Gemini API and the gemini-3.1-flash-image model, you can create more visually appealing and high-quality images.

As you move on to the practice exercises, take the opportunity to experiment with different combinations of styles and quality modifiers. This hands-on practice will reinforce your understanding and prepare you for more advanced topics in the upcoming lessons. Enjoy the creative process of generating stunning images with AI!