tools.loumo.jp

Image tools

Batch Image Watermark

Process images in your browser without uploading them.

Add images

You can also drop images here. Only the first GIF frame is processed. You can also drop a folder here; images in subfolders are included.

Files

    Saved in this browser. Input images and per-image rotations are excluded; the watermark image is included.

    Watermark

    Drop a watermark image anywhere in this box.

    Size and margin are percentages of output width. Image watermarks default to 20% width.

    Preview

    Add an image to see the result here.

    Output

    With conversion off, the original format is kept. HEIC, GIF, and BMP require conversion.

    Quality and size targets apply only to JPEG and WebP. A size target adjusts quality automatically; if unreachable, the smallest result is saved with a warning.

    Save

    Overwrite applies only when saving directly to a folder. When off, duplicate names receive _2, _3, and so on. When on, later images in the same batch also overwrite earlier files with the same name.

    Processed images are not kept in browser storage. You can download completed items after stopping.

      Overview

      Add text or image watermarks to multiple images. Save settings and the watermark image as a preset in this browser.

      Images are processed in your browser and are not uploaded to the server. Supported inputs are JPEG, PNG, WebP, BMP, GIF, and HEIC. Outputs are JPEG, PNG, and WebP.

      How to use

      1. Add multiple images or drag and drop them. Switch between thumbnail and list views. Select and remove unwanted images. You can also drop a folder here; images in subfolders are included.
      2. Add a text or image watermark and set its position, opacity, size, and margin. Save frequently used settings as a browser preset.
      3. Enable conversion to choose JPEG, PNG, or WebP. With conversion off, the original format is kept. HEIC, GIF, and BMP require conversion.
      4. Choose whether to preserve EXIF, remove only GPS, keep only the capture date, or remove all EXIF. Only compatible information is retained when converting formats.
      5. Choose a save method and start processing. Download the ZIP when ready, or choose a folder in a supported browser for direct saving.

      Key terms

      Pixels (px)

      A unit of image width and height. 1920 × 1080 means 1920 pixels wide and 1080 pixels high.

      Aspect ratio

      Normal resizing preserves this ratio. The Stretch method changes it.

      EXIF

      Image metadata that may contain the capture date, camera settings, and location. The fields vary by image.

      ZIP

      A file that bundles multiple processed images into one download.

      HEIC

      An image format commonly used on Apple devices such as iPhone and iPad. This tool can read HEIC but cannot output it.

      WebP

      An image format commonly used on websites to reduce file size. This tool can read and output WebP.

      Frequently asked questions

      Are images sent to the server?

      No. Processing happens in your browser; the images are not uploaded.

      Can animated GIFs stay animated?

      No. Only the first GIF frame is used, then saved as a still JPEG, PNG, or WebP image.

      Will the image dimensions change?

      This page has no resize setting, so width and height stay the same. Conversion can still change file size.

      Does “Preserve EXIF” keep everything?

      No. Some fields cannot survive format conversion. HEIC EXIF cannot be carried over. A warning appears if preservation fails.

      What if my images are too large for ZIP?

      ZIP input and output are each limited to 256 MB. Use direct folder saving in a supported browser for larger batches.

      What happens if I stop midway?

      You can download completed images as a ZIP on this page. Unsaved data is lost when you close it. Directly saved images remain in the selected folder.