Free Online Batch Image Optimizer
Your photo is decoded and edited in this tab. It stays local, including whatever its metadata says about where it was taken.
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How it works
One image in flight at a time, on purpose
Batch tools that decode everything at once fall over on phones. A decoded image costs width × height × 4 bytes of RGBA regardless of how small the file was, so twenty 12-megapixel photos is roughly a gigabyte of bitmap before any encoding starts. This processes strictly sequentially — decode, encode, release, next — which keeps peak memory at roughly one image and is why a long list finishes on a mobile browser instead of crashing the tab halfway through.
- Shared settings
- One quality, format and resize rule applies to every file in the run. Per-file tuning belongs in the single-image compressor.
- Sequential queue
- One image is decoded at a time. Progress is per file, and a file that fails to decode is skipped and reported rather than aborting the run.
- ZIP packaging
- Entries are stored, not deflated. Compressed images do not compress again, so the ZIP is about the sum of its parts and packs almost instantly.
- Filenames
- Original names are kept, with the extension changed to match the output format. Two inputs with the same name get a numeric suffix.
- Mixed inputs
- JPG, PNG and WebP can be mixed in one run. Converting them all to a single output format is usually the point.
How to use it
How to compress images in bulk online
- 01
Select the images
Drag a selection in or pick them. They are read from disk, not uploaded.
- 02
Set quality and format once
The same settings apply to the whole run, including an optional resize.
- 03
Download the ZIP
The archive is built in the browser from the results and saved straight to your downloads folder.
Where it earns its keep
Where batch image optimization earns its place
- Converting a shoot's worth of JPEGs to WebP before they go into a gallery.
- Getting every image in a blog post's folder under a page-weight budget.
- Resizing a product catalogue to a single maximum dimension.
- Stripping a client's photo set down to web sizes without uploading their work.
Questions
Batch Optimizer, answered
How many images can I process at once?
There is no hard cap, but the limit is your device's memory and patience rather than a plan tier. Processing is sequential, so a hundred files works — it simply takes a hundred files' worth of time, and on a phone very large images will be slower than on a laptop.
Are the files uploaded to be batched?
No. Each file is read from disk, processed and zipped inside this browser tab. Nothing is transmitted, which is why there is no upload progress bar and no waiting for a server slot.
Can I give different settings to different images?
No. A run applies one set of settings to everything, which is what makes it fast to configure. If two images need different quality levels, do them as two runs or use the single-image compressor for the awkward one.
Does closing the tab lose my progress?
Yes. The work happens in the page, so navigating away ends the run and completed results that have not been downloaded are gone. That is the direct trade for nothing being stored on a server.