Watermark Image FREE | Add Text Watermark to Photos Online

Add a custom text watermark to any image. The default diagonal tile mode fills the entire image with repeated watermark text at a 45-degree angle and the professional standard for copyright protection. Choose a single position instead, or adjust font size, colour, opacity, and angle. Preview live and download instantly. Nothing is uploaded.

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Full-Image Tile Mode

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Image Watermark Tool

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Frequently Asked Questions

Diagonal tile at 45 degrees is the professional standard for image copyright protection. It covers every part of the image so it cannot be removed by simple cropping, covers backgrounds and foregrounds equally, and is extremely difficult to remove from complex photographic backgrounds without visibly degrading the image. Stock photo agencies like Getty and Shutterstock use this exact pattern on their preview images.

The tile algorithm draws the watermark text repeatedly in a diagonal grid that extends beyond the image boundaries in all directions. This ensures the pattern fully covers every pixel even at any rotation angle. The step spacing between instances is calculated from the text width and font size so the tiling always looks even regardless of your text length or font size setting.

For stock photo preview protection, 35-55% opacity is the standard range. The watermark is clearly visible but the image content is still appreciable. For subtle branding on client deliverables, 15-25% keeps the mark visible but unobtrusive. The live preview updates as you type so you can judge the exact level visually on your own image.

Yes. The tiling loop extends 1.5 times the image diagonal in all directions before drawing, which mathematically guarantees full coverage at any rotation angle. The preview shows exactly what the downloaded image will look like.

The watermark is drawn onto a full-resolution canvas at the original image dimensions. JPG output uses 0.92 quality which is very high. PNG output is lossless. The watermark is the only change to the image content.

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Free Image Watermark Tool Online - Protect Your Photos with Full-Coverage Diagonal Watermarks

Watermarking is the primary visual copyright protection method used by photographers, illustrators, graphic designers, and stock image creators. The Image Watermark tool on OneDocPDF places professional-grade text watermarks using a diagonal tile algorithm that guarantees complete coverage of the entire image. Unlike simple centre-placement watermarks that can be cropped out, the tile mode at 45 degrees makes every pixel of the image carry the watermark, making removal extremely difficult without visibly degrading the photo.

The tiling algorithm draws the watermark in a repeating diagonal grid that extends well beyond the image boundaries in all four directions before clipping to the canvas. This mathematical approach ensures zero gaps at the corners and edges even at any rotation angle. Adjust font size to control how many instances appear across the image. Larger text with wider spacing looks bold and aggressive. Smaller text with tighter spacing creates a dense pattern that is effectively impossible to remove.

For a complete image workflow: Resize Image to reduce resolution before sharing, Compress Image to reduce file size, Add Text to Image for titles and captions, and Convert Image Format to change between JPG, PNG, and WebP. Browse all free image tools and PDF tools on OneDocPDF.