Image Compressor
- Free
- No upload
- No watermark
Quick answer
Drop in a photo and pull the quality slider until the file is small enough, watching the before and after side by side. Nothing leaves your device while you do it.
What it does
What the image compressor does
This is the general-purpose version of Toolvy's compressor: a quality slider from 1 to 100, an optional target-size box if you would rather type a number than eyeball a slider, and a live before/after comparison so you can see exactly where quality starts to fall apart.
Your format is kept by default. A JPEG is re-encoded with MozJPEG, the encoder Chrome and Facebook both use in production, and a WebP with libwebp. A PNG is redrawn with an optimized palette of up to 256 colors, the trick behind TinyPNG, which typically makes it 60 to 80 percent smaller with transparency kept. That step is lossy, so turn the Lossy PNG toggle off when every pixel has to stay exact; oxipng then repacks the file with no loss, for a much smaller saving. Two cases change format. HEIC and BMP have no encoder here, so an opaque one comes out as a JPG, and with a target size set, Auto turns a photo saved as PNG into a JPG, because a PNG photo cannot reach a small target any other way.
Because the slider is free-form rather than locked to a byte target, this page suits people who care about a ratio, not a ceiling: shrink a batch of product photos by roughly half, or find the point where a screenshot stops looking blocky.
Step by step
How to use it
- 01
Add your images
Drag files onto the drop zone or click to browse. Multiple files queue up for batch processing.
- 02
Set the quality
Drag the slider, or type a target size in KB and let Toolvy find a matching quality automatically.
- 03
Compare before and after
Drag the divider across the preview to check where detail is being lost, especially around text and hard edges.
- 04
Download
Save a single file, or grab every processed image at once as a ZIP.
Your images never leave your device
Every image is decoded and re-encoded on a canvas inside your own browser tab. That matters for the photos people do not want passing through a stranger's server: a listing photo for a property that has not gone on the market yet, or a screenshot of an internal dashboard that still has real customer data in it.
- No file is ever uploaded to a server
- Works offline after the first visit
- No account, no watermark, no limits
Get better results
Format and quality tips
- 01
Quality 75–85 is the sweet spot for JPEG
Below roughly 60 you start to see ringing artefacts around hard edges and haloing near text. Above 90 the file grows fast for a difference most people cannot see on a phone screen.
- 02
PNG will not shrink much if it is already a photo
PNG is lossless, so a photographic PNG is often larger than the same image at JPEG quality 90. If the source has no transparency and is not line art, converting to JPEG or WebP first will save far more space than any PNG optimiser can.
- 03
WebP beats JPEG at the same visual quality
libwebp typically produces files 25–35% smaller than MozJPEG for a comparable amount of visible detail loss, because its transform and entropy coding are newer. The trade-off is that a handful of older tools and print workflows still do not accept WebP.
A little more clarity
Frequently asked questions
01Does compressing an image reduce its resolution?
No, not by itself. Compression discards colour and detail information at the same pixel dimensions; the width and height stay identical unless you also resize.
02Why is my PNG bigger than my JPG?
PNG is lossless and JPEG is not. A JPEG throws away information your eye is unlikely to miss, while PNG has to store every pixel exactly, which costs far more space for photographs.
03How many times can I compress the same JPEG?
Every re-encode loses a little more information, a real effect called generation loss. One pass at quality 80 looks fine; five passes at quality 80 looks noticeably worse than one pass, even at the same setting.
04Will compressing strip my photo metadata?
Re-encoding through a canvas does not preserve EXIF data such as camera model or GPS location, so most metadata is dropped as a side effect. Use the EXIF remover if you specifically need to check what was there first.
05Is there a limit on how many images I can compress at once?
The practical limit is your device's memory, not a number Toolvy enforces. A modern laptop handles a few hundred phone photos in one batch without trouble.
06Should I use quality or the target-size box?
Use quality when you want consistent visual results across a batch, and target size when a form or upload limit gives you a hard byte ceiling to hit.
Guides
Further reading
- Guide6 min readHow to Reduce a Photo to 100KBA 100KB cap is a hard wall on an upload form, not a suggestion. Here is the resize-then-compress method that gets you under it while the photo still looks like a photo.Read the guide
- Guide6 min readHow to Compress an Image for EmailEmail attachment limits are smaller than the number they advertise, and your recipient is probably on a phone. Here is how to make photos that always arrive and always open.Read the guide
- Guide6 min readPNG vs JPG: Which Should You Use?The rule is short: photographs go to JPG, anything with sharp edges or transparency goes to PNG. This post explains why, so you never have to guess again.Read the guide
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