Add a watermark
Add your name or a logo.
Drop an image here
JPG / PNG / HEIC (Safari) · 20 MB · 25 MP
Drag the watermark, or use the position controls. With the preview focused, arrow keys move it; Shift moves faster.
Your image stays on your device.
How much a mark changes the picture
We added the text "LighterPics" at 30% of the image width, and a logo, to every test image.
Similarity to the same image without a mark
| Mark | Photos | Screenshots | Graphics |
|---|---|---|---|
| Text, bottom right, 5% | 0.991 | 1.000 | 1.000 |
| Text, bottom right, 30% | 0.987 | 1.000 | 1.000 |
| Text, bottom right, 70% | 0.985 | 0.999 | 0.999 |
| Text, bottom right, 100% | 0.984 | 0.998 | 0.999 |
| Text, center, 70% | 0.987 | 0.999 | 0.995 |
| Logo, bottom right, 70% | 0.963 | 0.974 | 0.987 |
Source: our test on 2026-11-10 (harness eacd79c, site code eacd79c), headless Chromium 145 on a desktop Mac, 25 CC0 photos and 14 images we made. Similarity is our own 8×8-block luma score (SSIM): 1.000 means no visible change, lower means more change. How we test
File size with the text at the default position and opacity
| Images | Saved as | Share of original |
|---|---|---|
| Photos | JPG | 60% |
| Screenshots | PNG | 141% |
| Graphics | PNG | 196% |
Source: our test on 2026-11-10 (harness eacd79c, site code eacd79c), headless Chromium 145 on a desktop Mac, 25 CC0 photos and 14 images we made. Sizes are a share of the original file size. How we test
How the watermark is placed
- Choose Text or Logo. Text is one line of up to 120 characters in this device's sans-serif font, in the color you pick. A logo is a second JPG or PNG; a transparent PNG keeps its shape.
- Width sets the mark's width as a share of the image width, from 5% to 80%. If that would make it taller than 90% of the image, it is made smaller.
- Horizontal and Vertical place the mark in the space left around it: 0% puts it against the left or top edge, 100% against the right or bottom. You can also drag it, use the five position buttons, or move it with the arrow keys, 1% a press or 5% with Shift.
- Opacity, from 5% to 100%, mixes the mark with the picture under it.
- Create image draws the picture and then the mark at full size. The pixel size does not change. JPG is saved again at quality 0.92; PNG keeps every pixel outside the mark.
- Each new image starts with the text LighterPics in white, 30% wide, at 70% opacity, near the bottom-right corner. Image and logo stay on your device.
Watermark limits
| Limit | Value |
|---|---|
| File size | 20 MB for the image and for a logo |
| Image in | JPG or PNG, up to 25 megapixels and 16,384 px per side |
| Text | One line, up to 120 characters |
| Width | 5% to 80% of the image width, and at most 90% of its height |
| Opacity | 5% to 100% |
| Marks | One per image, one image at a time |
| Format out | Same as in: JPG at quality 0.92, or PNG |
| HEIC (iPhone photos) | Opens in Safari, not in Chrome or Firefox. Why, and what to do |
| Location and camera data | Not copied: 0 of 360 files this tool made in our test had EXIF data. |
When a watermark goes wrong
Does adding a mark lower photo quality?
Slightly, for JPG, because the photo is saved again. With a faint mark at 5% our photos scored 0.991, close to the 0.993 the same photos scored when simply converted to JPG 92, so most of that change is the new save. PNG screenshots scored 1.000: outside the mark their pixels stay exact.
Can someone just crop the mark off?
Yes, if it sits near an edge, a point many watermarking guides make (user reports, for example this guide). A mark in the middle is harder to remove but covers the subject. In our test a centered mark changed photos about as much as a corner one (0.987 against 0.985). A visible mark tells people who made the image; it does not stop copying.
How big and how strong should the mark be?
This tool starts at 30% of the width and 70% opacity. Watermarking guides often suggest about a third of the width at about half opacity (user reports, for example this test). In our test, raising the text from 5% to 100% opacity moved photo similarity from 0.991 to 0.984; the logo scored 0.963.
Why is my watermarked PNG so much bigger?
The browser writes a new PNG, and its encoder packs less tightly than many apps: our screenshots came out at 141% of their file size and graphics at 196%. Why new files can grow. Photos, saved as JPG, came out at 60%.
Can I mark many photos at once?
No. This tool marks one image at a time with one mark, and has no repeating pattern.
Make it your own
- Choose a JPG or PNG image. The image and optional logo stay on your device.
- Enter text or choose a logo. Adjust width and opacity, then drag it or pick a position. The mark fits inside the image.
- Create and check the download. Reset removes the logo and restores default text settings.
Does a watermark prevent copying?
No. It is a visible label, not copy protection or proof of ownership. One mark is added without changing pixel dimensions or removing existing marks. Source metadata is not copied; this is not a forensic metadata-removal guarantee.
Place a logo without covering the subject
A visible mark identifies the version you share but does not stop copying or editing. Use a mark you have permission to use and keep an unmarked original.
Choose the landscape PNG and example logo. Select Logo, width 30%, opacity 70%, then the bottom-right preset (95%, 95%). Create the image to apply the mark.
Download example logo (PNG · 320 × 96 px)
The image stays 960 × 640. The logo is 288 pixels wide, 30% of the image width. Position percentages describe movement within the space left around the mark, so 95% is near the edge without clipping.
Original illustrations created by LighterPics and processed with this tool. Real example files, not predictions for your image. File sizes can vary by browser.
Measured: · Chromium 145.0.7632.6
Why does my logo have a white rectangle?
The example logo has an opaque background on purpose. For just the logo shape, use an already transparent PNG. Lower opacity fades both logo and background; it does not remove the background.
How do I keep the mark readable?
Check the output at full size and at its viewing size. Avoid busy details and adjust size or opacity. Text uses device fonts, so appearance varies. This tool adds one mark, not a repeating pattern.