A powerful and fast CLI tool for image processing, built with Go, Cobra, and Viper.

Link: https://github.com/PrathamGhaywat/imgtool

• Format Conversion: Convert images between png, jpg, gif, and webp.
• Quality Adjustment: Set the quality for lossy formats like jpg and webp.
• Image Resizing: Resize images using specific dimensions (e.g., 800x600) or by a percentage (e.g., 50%). Aspect ratio is preserved if one dimension is set to 0.
• Watermarking: Apply a watermark image with adjustable opacity.
• Batch Processing: Process a single file or an entire directory of images.
• Concurrency: Use multiple workers for faster directory processing.
• Configuration: Set default flag values using a config.yaml file.

Install the release from here. Then add the folder in which the executable is present in your PATH environment variable.

We are currently searching for a way to make the tool available for Linux and macOS. Please open an issue if you have any suggestions. If you would still like to use the tool on Linux and macOS, you can build it from the source.

The documentation for imgtool can be found here.

To build the tool from the source, you'll need to have Go installed.

# Clone the repository
git clone https://github.com/PrathamGhaywat/imgtool.git
cd imgtool

# Download dependencies
go mod tidy

# Build the executable
go build -o imgtool.exe .

To see a list of all available commands and flags:

.\imgtool.exe --help

The convert command is the primary tool for all image processing tasks.

.\imgtool.exe convert [input_path] [output_path] [flags]

• input_path: The path to the source image or directory.
• output_path (optional): The path for the output file or directory. If omitted for a single file, the output will be saved in the same directory with the new format extension.

• --to <format>: The target format (png, jpg, gif, webp). Default: png.
• --quality <int>: Image quality for jpg/webp (1-100). Default: 80.
• --resize <string>: Resize dimensions (e.g., "800x600" or "50%").
• --watermark <path>: Path to the watermark image.
• --watermark-opacity <int>: Watermark opacity (0-100). Default: 100.
• --mode <string>: Processing mode (single or dir). Default: single.
• --recursive: Recursively process subdirectories in dir mode.
• --workers <int>: Number of concurrent workers for dir mode. Default: 4.

1. Convert a PNG to a high-quality JPG

   .\imgtool.exe convert input.png output.jpg --to jpg --quality 95

2. Resize an image to 50% of its original size

   .\imgtool.exe convert big.jpg small.jpg --resize "50%"

3. Apply a watermark to an image

   .\imgtool.exe convert photo.png watermarked.png --watermark logo.png --watermark-opacity 70

4. Process an entire directory of images

   This command converts all images in the input-folder to webp and saves them in output-folder.

   .\imgtool.exe convert input-folder output-folder --mode dir --to webp

You can set default values for any flag in the config.yaml file. The tool looks for this file in the current directory or your home directory.

Example config.yaml:

# Default configuration for imgtool
to: "webp"
quality: 75
watermark: "C:/Users/YourUser/Pictures/watermark.png"
watermark-opacity: 60
workers: 8