Free
Optimizilla
Compresses a batch of images entirely inside your browser, with a quality slider per image and nothing uploaded.
FreeBeginnerWeb
Overview
Optimizilla shrinks image file sizes, and it does the whole job inside your browser. The site states nothing is uploaded to any server, so your pictures stay on your machine. You can compress a batch at once and get them back as a zip, and each image gets its own quality slider instead of one setting for the set. It takes JPEG, PNG, WebP, GIF and SVG.
It is free. You do not need an account, there is no daily limit, and it adds no watermark. The site states it strips all metadata, including EXIF, GPS and camera details, with no option to keep it.
Key features
✓Compresses entirely in your browser, nothing uploaded
✓Batch a set of images, returned as a zip
✓A quality slider per image, not one for the set
✓Comparison view of original against compressed
✓Colours slider for PNG & GIF palette reduction
✓Takes JPEG, PNG, WebP, GIF & SVG
✓Free with no registration or daily limit
✓No watermark on results
✓Strips EXIF, GPS & camera info automatically
When to use
Use Optimizilla if:
- You have a folder to compress and the images are confidential. The compression runs on your machine and takes a batch.
- You want to control each image separately, since every file gets its own quality slider rather than one setting for the set.
- You want to see what you are losing, which the comparison view shows before you download.
- You are compressing PNGs or GIFs, where the colours slider is the control that shrinks them.
- You want the location data gone from photos before posting them, which it strips automatically.
- You want to skip accounts, daily caps and watermarks, which is what it offers.
When NOT to use
Skip Optimizilla if any of these describe you:
- You need the EXIF data kept. It removes all metadata automatically, including camera settings and dates, with no option to keep them. An EXIF tool is what you want if that data matters.
- Your photo needs to be smaller in dimensions, not only in file size. This compresses only, so ImageResizer.com handles the pixels.
- You need to hit a named file size in kilobytes or megabytes. PicResize lets you specify the target.
- Your batch is large. It takes 20 images per batch, and other image compressors handle bulk work differently.
Frequently asked questions
No. The site states all processing happens in your browser using WebAssembly, and that there are no uploads to any server. Your files stay on your machine and the compression runs on your own processor. That is the reason to use it over an ordinary online compressor, which sends everything to somebody's servers. For client work, documents or anything confidential, this removes the question entirely rather than asking you to trust a deletion promise.
Yes, up to 20 images at a time, and it returns them as a single zip. Each file can be up to 50 MB. Local processing often means one file at a time, since the work runs on your own machine. Squoosh compresses locally too, but handles one image at a time.
Yes, automatically, and you are not asked. The site states all metadata including EXIF, GPS and camera information is removed from compressed images. Whether that is good or bad depends entirely on you. If you are posting photos publicly, having the GPS coordinates stripped is a genuine benefit most tools do not give you. If you catalogue your photos by camera settings or shooting date, that information is gone from the compressed copy, so keep your originals.
Because PNG and JPEG get smaller in completely different ways. JPEG throws away detail your eye is unlikely to miss, so a quality setting decides how much. PNG keeps every pixel exactly, so the only real way to shrink it is to use fewer distinct colours, which is what the palette slider does. GIF works the same way. That is why the tool shows you a different control depending on the format. A screenshot with flat colour shrinks a lot, while a photograph saved as PNG barely moves.
No. It changes the file size and leaves the dimensions alone, so an image that is too many pixels wide for a website comes out exactly as wide, only lighter. Those are different problems: resizing changes how many pixels there are, compressing changes how efficiently they are stored. If your image needs both, resize it somewhere else first and compress the result here.
Alternatives to Optimizilla
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Compressor.io
Shrinks an image file as far as it can, lossy or lossless, and lists the size saved for every file.
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ShortPixel
Compresses JPG, PNG and animated GIF images with a choice of three strengths, and converts them to WebP or AVIF for the web.
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