Text watermarks
Add a name, website, copyright notice, photo credit or status such as DRAFT.
Add a watermark to images online
Add text, copyright information or a logo to as many as 25 JPEG, PNG or WebP images. Choose the size, opacity, rotation and position while processing everything inside your browser.
25images per batch2watermark types0image uploads
Private batch watermarking
Design your watermark, then add images
No upload
Drop images hereor choose files from your device
JPEG, PNG or WebP · Up to 25 images · 25MB per image
Original size0 B
Output sizePending
Size changePending
Batch-ready One design across 25 imagesFlexible Text, logo, position or tilePrivate Files stay on your device
One design, a complete batch
Protect and brand images with consistent controls
Create one watermark design and apply it automatically to every image in the current batch.
Logo watermarks
Use a PNG, JPEG or WebP logo image with adjustable opacity and relative size.
Position or tile
Choose nine clear positions or repeat the watermark across the full image.
Batch download
Download one result or collect every completed image in a single ZIP file.
How to watermark images
Design, add and download in three steps
Settings lock while images remain so the batch cannot silently contain different watermark designs.
Create the watermark
Choose text or a logo, then set opacity, size, rotation and position.
Add up to 25 images
Drag images into the tool or browse your device. Processing starts automatically.
Review and download
Check every result and download individually or create one ZIP for the batch.
Format-aware output
Watermark JPEG, PNG and WebP images
The source format and pixel dimensions remain unchanged. Transparent PNG and WebP content stays supported.
Watermark JPEG photographs
Progressive MozJPEG quality 88 provides a strong quality balance for photographic output.
Watermark transparent PNG
PNG output remains lossless and passes through OxiPNG while supporting transparent pixels.
Watermark WebP images
WebP output uses quality 88 and full alpha quality for transparent watermark workflows.
Controlled, honest output
A watermark is added without changing dimensions
The tool draws the chosen watermark onto the decoded image at its original width and height. Text and logo opacity are applied consistently across the batch.
Because the image is re-encoded after adding visible content, its file size may become smaller or larger. ImageOptimise reports the actual result rather than describing every change as a saving.
A watermark discourages casual reuse but cannot guarantee copyright protection. Keep original unwatermarked master files separately.
Current optimiser safeguards
✓Original pixel dimensions remain unchanged.
✓PNG and WebP transparency remains supported.
✓The selected watermark is applied consistently to the whole batch.
✓Actual file-size changes are reported honestly.
Practical watermarking
Add ownership, status or branding before sharing
Watermarks are useful wherever an image may be distributed beyond its original source.
Photography proofs
Add a name or repeated proof mark before sending previews to clients.
Property listings
Apply an agency logo consistently across property photographs.
Online marketplaces
Brand product images before publishing them on listing platforms.
Design approval
Mark unfinished artwork as DRAFT or CONFIDENTIAL.
Social content
Add a creator name, handle or website to shareable images.
Photo credits
Place a readable credit line in a consistent corner position.
Private browser watermarking
Your original images stay in the current tab
Supported files are decoded, watermarked and encoded locally. Image bytes, filenames and watermark text are not sent to an ImageOptimise processing server.
- No account or image upload endpoint is required.
- Each browser tab has an independent temporary batch.
- Different devices on the same network cannot access one another’s images.
- Clear All or close the tab to end the temporary session.
Watermark questions
Frequently asked questions
Key details about logo files, transparency, position and output.
Can I add a text or logo watermark?＋
Yes. Choose text with a custom colour, or select a PNG, JPEG or WebP watermark image up to 5MB.
Can I watermark several images together?＋
Yes. One design can be applied to up to 25 images, each no larger than 25MB.
Can the watermark repeat across an image?＋
Yes. Select Repeat across image instead of one of the nine fixed positions.
Will the image dimensions change?＋
No. The output keeps the decoded width and height of the source image.
Can I change opacity, size and rotation?＋
Yes. Use the three controls before adding images. Settings lock during the batch for consistency.
Will PNG transparency remain?＋
Yes. Transparent PNG and WebP output remains supported.
Why can the output file be larger?＋
Adding visible content requires re-encoding. Depending on the source and format, the resulting file may be smaller or larger, and the actual change is shown.
Are my images uploaded?＋
No. Supported images are processed inside the current browser tab.
Protect your images
Watermark images now
Watermark your next image batch
Create one text or logo watermark and apply it privately to up to 25 images.