Batch Image Watermark Tool for Windows – Free & Fast

In our day-to-day website operations, e-commerce product launches, and brand promotion efforts, we often need to add brand logo watermarks to large numbers of real-life photos and product images. Processing them one by one in Photoshop is too time-consuming, and many of the small tools available on the market either severely compress image quality or don’t support complex tiling and rotation. To completely solve this problem, I used Rust + egui A desktop graphical application has been developed—Watermark Tool (Batch Image Watermarking Tool). Not only does it support a variety of complex layout engines—such as single-point and tiled layouts—but it also utilizes multithreading to enable batch exports in a matter of seconds, perfectly balancingHigh Performance与Foolproof operation。

GitHub Project Repository：https://github.com/cheng01315/batch-image-watermark

🎯 1. Key Features and Highlights

1. 1 A Watermark Layout Engine That Lets You Do Whatever You Want

Single Watermark Mode: 9 preset anchor points (top-left / top-center / top-right / left-center / center / right-center / bottom-left / bottom-center / bottom-right), with support for pixel-level fine-tuning of margins and X/Y positions.
Full-Screen Tile Mode: Offers three anti-collision tiling strategies—Standard Grid, Brick, and Diagonal—with independent X and Y axis spacing settings.
Rotate to any angle: Supports ±180° rotation of watermarks, making it easy to create a tilted anti-theft effect.

1.2 Professional-Grade Watermark Effects and Image Quality Control

Perfect Transparency Blending: 0% ~ 100% freely adjustable, with precise blending of the alpha channel for a seamless result.
Smart Zoom: Supports scaling based on a percentage of the original image size, or specifying an absolute pixel width.
Lanczos3 Resampling: Using a high-quality resampling algorithm ensures that the scaled-down logo remains crisp, eliminating blurriness and jagged edges.

1.3 Lightning-Fast Batch Export Engine

Multithreading and Concurrency: Rust-based rayon With our parallel library, you can fully utilize your multi-core CPU to process hundreds or even thousands of images in an instant.
Smart Naming Conflict Strategy: Supports automatic renaming (appending _wm (suffix), overwrite the file with the same name, or skip it to prevent accidental operations.
Flexible Format Conversion: Supports PNG, JPEG, BMP, and WebP input. When exporting, you can keep the original format or convert all files to JPEG (with adjustable quality) or PNG.

🖼️ 2. Minimalist User Interface

The tool uses the classic“Control Panel on the Left + Canvas on the Right”Layout. After modifying the parameters, on the right sideLive Preview(Automatically resizes to fit the window), and features a native file selection dialog and Toast notifications, providing you with a seamless desktop experience.

Watermark Tool: User Interface for Batch Image Watermarking — Watermark Tool Real-Time Preview and Parameter Adjustment Interface

📌 Suggestions: For watermark images, we recommend using images with a transparency channel. PNG format, which produces the best results.

🎮 3. How to Add Watermarks to Multiple Images in Six Steps

Step 1: Select a watermark design — Upload your brand logo (transparent PNG recommended).
Step 2: Import the images to be processed — You can select a single image or an entire folder (the system will automatically recursively search subfolders).
Step 3: Adjust the watermark settings — Use the left-hand panel to adjust the position, tiling strategy, transparency, zoom level, or rotation angle.
Step 4: View a Live Preview — Preview the final composite directly on the canvas on the right; what you see is what you get.
Step 5: Set the output options — Select the export format (JPEG/PNG), compression quality, and filename conflict policy.
Step 6: Start batch export with one click — Click "Export" to view the export speed via the real-time progress bar. Once complete, a detailed report will pop up showing the counts for successes, failures, and skips.

🛠️ 4. Developer Guide: Minimalist Single-File Architecture

If you're also a Rust enthusiast, this project is a great way to learn the language. egui An open-source example of UI development and image processing. The project's source code consists of approximately 1,600 lines, all contained in main.rs The structure is clear within a single file.

Technology Stack Overview

Category	Core Library	Uses
GUI Framework	`eframe` + `egui` (v0.28)	Immediate Mode Cross-Platform Desktop UI
Image Codecs	`image` + `imageproc`	Responsible for multi-format reading and writing, affine transformations, and Alpha blending
Concurrency Acceleration	`rayon`	Parallel Batch Processing That Fully Utilizes Multi-Core Performance
System Interaction	`rfd` + `directories`	Calling the Native File Dialog and Cross-Platform User Configuration Persistence

Release Compilation Optimization

The project is in Cargo.toml The medium setting features extreme volume optimization (enabled lto = "fat"、codegen-units = 1、strip = true、panic = "abort"). The final compiled Windows single-file EXE is only 5–8 MB...with no external DLL dependencies—it’s truly portable and installation-free; just download and use it!

📌 5. Details on Supported Image Formats

Format	Read (Input)	Export (Output)	Notes
PNG	✅ Supported	✅ Supported	Supports high-quality transparent channel mixing
JPEG	✅ Supported	✅ Supported	You can freely adjust the image quality factor from 1 to 100 during export.
BMP	✅ Supported	❌ Needs to be converted	When exporting, all files must be converted to JPEG or PNG.
WebP	✅ Supported	❌ Needs to be converted	When exporting, all files must be converted to JPEG or PNG.

Please visit our GitHub repository and give it a star to show your support! If you have any feature suggestions while using the tool (such as adding text watermarks or font options), feel free to leave a comment below or open an issue on GitHub.