Batch tools · 50 files at a time
Bulk Image Tools
Six tools that do the same thing to a whole folder at once — and do it on your own machine, not on ours.
When a batch tool is the right tool
Batch processing is worth it when one decision covers every file. A portal that refuses images over 1600 px, a stack of scans that all came in sideways, a folder of iPhone HEIC photos that a form will not accept — in each case the rule is the same for the whole set, so the only work left is mechanical repetition. That is what these pages remove. When each photo needs its own judgement, a batch tool is the wrong shape and the single-image version of the tool will be faster.
These tools also beat installing a desktop app for the common cases, because there is nothing to install and nothing to learn: the whole interface is a drop zone, one or two settings, and a ZIP at the end. A desktop app still wins when you need thousands of files, scripted rules, colour management, or formats a browser cannot write such as TIFF and RAW. That is a real boundary and it is worth knowing before you start.
Nothing is uploaded. Every tool below decodes, processes and re-encodes each file inside your browser tab. There is no server queue and no account, which is also why the ceiling is 50 files and 200 MB per batch — your own device holds every decoded image in memory while it works.
The six tools, side by side
The column that usually decides which page you want is the last one: what survives the operation untouched.
| Tool | Reads | Writes | One setting covers | Keeps intact |
|---|---|---|---|---|
| Bulk Image Resizer | PNG · JPG · WebP · GIF · BMP · HEIC | JPG · PNG · WebP | One sizing rule for the whole set | Aspect ratio, in every mode except “exact size” |
| Bulk Image Compressor | PNG · JPG · WebP · GIF · BMP | JPG · WebP · PNG | Output format and quality | Pixel dimensions — only the bytes change |
| Bulk Image Converter | PNG · JPG · WebP · GIF · BMP · HEIC | JPG · PNG · WebP | One target format for a mixed input set | Pixel dimensions and, in PNG/WebP, transparency |
| Bulk Image Cropper | PNG · JPG · WebP · GIF · BMP | JPG · PNG · WebP | Aspect ratio plus which part of the frame to keep | Original pixel density — it trims, it never scales |
| Bulk Image Rotator | PNG · JPG · WebP · GIF · BMP | JPG · PNG · WebP | One angle, plus optional mirroring | Every pixel at 90/180/270 degrees |
| Bulk Grayscale Converter | PNG · JPG · WebP · GIF · BMP | PNG · JPG | Output format only — the conversion itself is fixed | The alpha channel, when the output is PNG |
Pick a batch tool
Bulk Image Resizer
Drop a folder of photos, set one rule, and every file comes back at the new size. Nothing is uploaded — the resizing happens on your own machine.
OpenBulk Image Compressor
Shrink a whole folder of photos in one go, with the real before-and-after size on every row. The encoder runs in your tab, so nothing is uploaded.
OpenBulk Image Converter
Point a mixed folder at one target format. PNG, JPG, WebP, GIF, BMP and iPhone HEIC files all go in; PNG, JPG or WebP comes out.
OpenBulk Image Cropper
Give every photo the same shape. Pick a ratio and which part of the frame to keep, and each file is trimmed to the largest rectangle that fits.
OpenBulk Image Rotator
Turn or mirror a whole folder in one action. Quarter turns are lossless in framing; custom angles are available when a scan came in crooked.
OpenBulk Grayscale Converter
Convert a whole set of images to black and white with a single, predictable formula — and keep the transparency if you output PNG.
OpenLimits that apply to all six
- 50 files and 200 MB per batch. Anything past the ceiling is left out of the queue and the page says so.
- Files are processed one at a time. These are main-thread canvas operations; running four at once would jank the page without finishing sooner.
- One file failing never kills the batch. That row goes red with its reason, the ZIP still contains the successes, and “Retry failed” re-queues only the broken ones.
- Metadata does not survive. Every tool re-encodes on a canvas, so EXIF, GPS and colour profiles are dropped from the output. Work on copies if a shoot needs its metadata.
- Animated GIFs become still images. A canvas only ever sees the first frame.
- Progress is not faked. A row shows movement while it is working and turns green when it is done, because a single-pass canvas operation has no honest mid-way percentage. The batch bar is a real count of finished files.