Batch Image Converter

Batch Image Converter is a professional Windows desktop application for converting, resizing, and enhancing entire image folders in one pass. It is built with .NET 10 and Avalonia UI and is donationware: download it, use every feature for free, and support development with an optional donation.

Download

The latest release is available on GitHub Releases. The Windows build requires the .NET 10 Desktop Runtime.

Key Features

Batch conversion - Convert entire folders between JPG and PNG with adjustable JPEG quality.
Resize and normalize - Set exact width and height, preserve original dimensions, or resize only images taller than a target height.
High-quality resampling - Choose bicubic, Lanczos, or spline-style cubic resampling.
AI image enhancement - Improve low-resolution or soft images with OpenAI, OpenRouter, or Google Gemini image models.
Encrypted settings - Provider API keys are encrypted with AES-GCM and stored under %APPDATA%\BatchImageConverter.
Professional dark theme - A clean Avalonia interface with sidebar navigation, progress reporting, and clear status messages.
Reliability - Serilog rolling logs, structured bug reports, automatic update checks, and anonymous startup statistics.
Donationware - Every feature is free. The donation banner disappears after a completed donation is verified for the email saved in the app.

AI Providers

Provider	Default model	Notes
OpenAI	`gpt-image-1`	Uses the image edits endpoint with the selected prompt.
OpenRouter	`google/gemini-2.5-flash-image-preview`	Choose an image-capable model available to your account.
Google Gemini	`gemini-2.5-flash-image`	Uses the generateContent API with image output modalities.

How It Works

Select the input folder that contains the source images and the output folder for the results.
Choose the output format, dimensions, JPEG quality, and resampling algorithm.
Run a conversion command, or switch to the AI enhancement page and run the enhancement command.
Review the processed, skipped, and failed counts when the batch finishes.

Data and Privacy

Settings, including provider API keys, are stored encrypted under %APPDATA%\BatchImageConverter. Logs are stored in the same application folder. Images are sent to an LLM provider only when you run AI enhancement. The app also sends anonymous startup statistics, donation verification requests, update checks, and warning-or-higher bug reports to Pure Logic Code endpoints.

System Requirements

Windows 10 or later
.NET 10 Desktop Runtime
An API key from at least one supported LLM provider for AI enhancement

Support Development

Batch Image Converter is free to use. If it saves you time, consider making a donation. After donating, use the app's I already donated button to hide the donation banner.

Batch Image Converter