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Image Watermark Tool
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Add custom watermarks to your images online to quickly protect your copyright and prevent image theft.
Click or drag images to add text / image watermarks (batch supported)
Image (Supported formats: .avif, .bmp, .gif, .jpeg, .jpg, .png, .webp)
Max 1 MB
Pixel to Centimeter Converter
Input pixel values and PPI to instantly convert to corresponding physical length in centimeters, also supports reverse conversion from centimeters to pixels, suitable for graphic design, UI slicing, and print layout.
Pixel to Millimeter Converter
Convert between pixels and millimeters based on PPI density. Supports custom density values, ideal for UI design and print layout.
PX to REM Converter
A bidirectional PX to REM converter for front-end developers and designers, featuring customizable root font sizes.
To address the pain point of original images being stolen or reposted without permission, this tool uses image compositing algorithms to overlay custom text or a semi-transparent logo onto your original image at specified coordinates. It directly outputs a new image with a copyright mark, establishing ownership of your work from the source.
We recommend uploading files no larger than 20MB for optimal single-image processing performance. Watermark opacity should ideally not be lower than 15%, otherwise it may affect the viewing experience of the original image. This tool operates entirely on the front end. All image data is processed in your local browser memory and automatically released upon completion; nothing is saved to any cloud servers. If you experience rendering delays, please check your browser version or try refreshing the page.
For image copyright protection, we recommend using a "diagonal tiled + high transparency" or "semi-transparent overlay on key subjects" watermark strategy. This effectively increases the difficulty of watermark removal without overly disrupting the visual composition. For e-commerce or design portfolios, you can combine this with an EXIF metadata writing tool for dual copyright authentication. If you need to batch process multiple images of varying sizes, it is advisable to standardize the crop ratio first or use scripts to call the Canvas API for automated pipeline compositing.
