Watermark image
Stamp one image onto another as a watermark, on your device.
Runs on your device. The file is never uploaded.
Watermark image takes exactly two files, the base picture first and the mark second. The mark is blended in at 20% of the base width, 50% opacity and bottom-right with a 16 pixel margin, leaving the base dimensions unchanged. The blend follows the mark's own alpha, so a JPG mark stamps its background down as an opaque box.
Questions
How many files do I drop, and in what order?
Exactly two, base image first and watermark image second. The order is the order they appear in the list on the page. Any other count stops with "image-watermark needs exactly 2 files (base image, then watermark image), got 3". There is no text watermark option here; your watermark is an image file, so make a PNG of your logo or text first.
Why does my watermark sit in an opaque box?
Because the blend is driven by the alpha channel of the watermark file, and a JPG has none, so every pixel including its background is stamped down. Use a PNG or WebP watermark with a genuinely transparent background. The Watermark opacity option, 0 to 100 with a default of 50, then scales that transparency further.
How is the watermark sized and placed?
Watermark width is set as a percent of the base image width, default 20, and the height follows to keep the watermark proportions. Where to place the watermark offers top-left, top-right, bottom-left, bottom-right and center, defaulting to bottom-right, with Margin from the edge in pixels, default 16. Center ignores the margin. Placement is clamped so a watermark larger than the base still lands inside it.
Can I tile the watermark across the whole image?
No. It is stamped once, at the one position you choose. There is no tiling, no rotation, no diagonal repeat and no opacity gradient. Running the tool twice with different positions is the practical way to get more than one mark.
What do I get back?
One file, named from the base image with a -watermarked suffix in the base image format, such as photo-watermarked.jpg, encoded at the Quality option, default 80, for JPG and WebP. The base image dimensions do not change. Both files are read and combined in a Web Worker on your device, and neither is uploaded.