Gemimg: Fixing --image_size Argument Not Passed To Generate()

by Alex Johnson 62 views

If you're a user of the Gemimg library and have encountered an issue where the --image_size argument seems to be parsed correctly but isn't actually affecting the output image size, you're not alone. This article delves into the root cause of this problem and provides a clear explanation, along with solutions and workarounds.

Understanding the Issue: The Missing image_size Parameter

The core of the problem lies within the gemimg/__main__.py file, specifically in the generate() method call. As highlighted in the original issue, the --image_size argument, although parsed from the command line, is not being passed to the generate() function. Let's take a closer look at the relevant code snippet:

result = gem_img.generate(
    prompt=args.prompt,
    imgs=args.input_images,
    aspect_ratio=args.aspect_ratio,
    resize_inputs=args.resize_inputs,
    save=False,
    temperature=args.temperature,
    webp=args.webp,
    n=args.n,
    store_prompt=args.store_prompt,
    # image_size=args.image_size  <-- missing
)

Notice the commented-out # image_size=args.image_size line. This clearly indicates that the image_size argument, despite being parsed and stored in args.image_size, is never actually utilized when calling the generate() function. This omission is the reason why you might be specifying an image size via the command line, but the output images consistently default to the library's default size (2048x2048 in this case).

This oversight means that regardless of whether you use a command like gemimg "red circle" --model gemini-3-pro-image-preview --image_size 1K -o test.png, the resulting test.png will still be 2048x2048 pixels. The --image_size argument is effectively ignored.

Demonstrating the Problem: Reproduction Steps

To further illustrate the issue, the original report provided a clear set of reproduction steps. Let's break them down:

  1. Running the command with --image_size:

    gemimg "red circle" --model gemini-3-pro-image-preview --image_size 1K -o test.png

    This command instructs gemimg to generate an image of a red circle, using the gemini-3-pro-image-preview model, and sets the desired image size to 1K (1024x1024 pixels). The output is saved as test.png.

  2. Checking the output image size:

    file test.png  # PNG image data, 2048 x 2048

    Using the file command, we can inspect the generated image's metadata. The output confirms that test.png is 2048x2048 pixels, despite specifying --image_size 1K. This confirms the issue: the --image_size argument had no effect.

The Python API Workaround: A Temporary Solution

Interestingly, the issue only seems to affect the command-line interface. The Python API, as demonstrated in the original report, works correctly:

from gemimg import GemImg
gem = GemImg(model='gemini-3-pro-image-preview')
result = gem.generate('red circle', image_size='1K', save=False)
print(result.images[0].size)  # (1024, 1024)

In this snippet, the image_size parameter is passed directly to the generate() method within the Python code. The output (1024, 1024) confirms that the image is generated with the specified size. This discrepancy highlights that the underlying image generation logic correctly handles the image_size parameter; the problem lies solely in how the command-line arguments are processed.

Therefore, if you need to generate images with specific dimensions using Gemimg, the Python API provides a reliable workaround until the command-line issue is officially resolved.

Why is this important? Setting custom image sizes.

The ability to specify image size is crucial for various reasons in image generation. Correctly implementing and utilizing the --image_size argument, or its equivalent in an API, is important for the following reasons:

  • Resource Management: Generating large images consumes more computational resources and time. If you only need a smaller image, specifying the size saves processing power and reduces generation time.
  • Storage Efficiency: Larger images take up more storage space. Specifying smaller sizes helps optimize storage usage, especially when generating numerous images.
  • Application Requirements: Different applications have different image size requirements. For example, a profile picture might need to be small, while a banner image needs to be larger. The flexibility to control image size ensures the generated images fit the intended use case.
  • Aesthetic Control: Sometimes, the desired aesthetic requires specific dimensions. Controlling image size allows for fine-tuning the output to achieve the desired visual effect.

Therefore, the ability to specify image size is not just a convenience but a crucial feature for efficient and effective image generation.

Proposed Solutions and Next Steps

The most straightforward solution is to modify the gemimg/__main__.py file and uncomment the # image_size=args.image_size line, ensuring that the parsed image_size argument is passed to the generate() function:

result = gem_img.generate(
    prompt=args.prompt,
    imgs=args.input_images,
    aspect_ratio=args.aspect_ratio,
    resize_inputs=args.resize_inputs,
    save=False,
    temperature=args.temperature,
    webp=args.webp,
    n=args.n,
    store_prompt=args.store_prompt,
    image_size=args.image_size  # <-- Un-comment this line
)

By making this simple change, the command-line interface will correctly pass the --image_size argument to the generation function, allowing users to control the output image dimensions.

For Gemimg Developers:

  • A pull request should be submitted to the Gemimg repository with the fix. This will ensure that the fix is incorporated into future releases of the library.
  • Consider adding unit tests to verify that the --image_size argument works as expected, preventing similar issues in the future.

For Gemimg Users:

  • If you're comfortable modifying the library's code, you can apply the fix locally as described above.
  • Alternatively, use the Python API workaround for now.
  • Monitor the Gemimg repository for updates and new releases that include the fix.

In Conclusion:

The issue with the --image_size argument in Gemimg is a clear case of a simple oversight leading to a significant usability problem. By understanding the root cause and implementing the proposed solution, users can regain control over the output image dimensions when using the command-line interface. In the meantime, the Python API provides a reliable alternative for specifying image sizes. Remember to stay updated with the latest releases and contribute to the community by reporting issues and suggesting improvements.

For more information on image generation and related topics, visit OpenAI Documentation. This external link provides valuable resources and insights into image generation techniques and best practices.