Protect your photos with text or logo watermarks. Batch process, precise positioning, adjustable opacity — all in your browser.
Click to browse or drag & drop images
Supports JPG, PNG, WebP up to 10MB each
The fastest, most private way to protect your images — add text or logo watermarks in seconds.
Add custom text or upload your own logo as a watermark. Text supports any font size, color, and rotation. Logos work best as transparent PNGs.
Place your watermark anywhere with a 9-position grid. Top, center, bottom × left, center, right — precise placement for any composition.
Fine-tune watermark visibility from subtle (10%) to bold (100%). Perfect balance between protection and aesthetics.
Apply the same watermark to dozens of photos at once. Set your watermark once, then batch process all images in parallel.
Rotate your text watermark to any angle. Diagonal watermarks are harder to crop out and look more professional.
Your photos and logo never leave your device. All watermark compositing happens locally using Canvas API — zero uploads, total privacy.
Three simple steps to protect your images.
Click or drag-and-drop your photos — JPG, PNG, or WebP up to 10MB each. Upload your logo as a transparent PNG if using image watermark.
Type your text or upload your logo. Choose position from the 9-point grid, adjust opacity, font size, color, and rotation. Preview updates in real time.
Click Download to save each watermarked photo individually, or use Download All for batch results. All files are output as PNG for maximum quality.
Everything you need to know about watermarking images with SlimImg.
Currently you choose either text or logo per session. For multiple watermarks, you can watermark with text first, download, then re-upload and add a logo watermark as a second pass.
PNG with a transparent background works best. Our Canvas compositing preserves the transparency, so your logo blends naturally into the photo without a white box around it.
The batch mode applies the same watermark to all uploaded images. For different text per image, process them one at a time in single-image mode.
We output watermarked images as PNG to preserve maximum quality. The original photo pixels are unchanged — only the watermark layer is composited on top.
Never. All watermarking happens entirely in your browser using the Canvas API. Your photos and logo never leave your device — 100% private and secure.
This tool is for adding watermarks, not removing them. Once a watermark is baked into the output PNG, it cannot be removed. Always keep an un-watermarked original.