🗜️ Image Compressor
By Shihab Mia · Updated 2026-07-30
JPG, PNG, WEBP or any image your browser can open. Nothing is uploaded.
Lower quality means a smaller file. 0.7 to 0.85 is a good balance.
Choose an image to get started.
This image compressor shrinks the file size of a photo or graphic without you leaving the page. Choose an image, pick JPEG or WEBP and a quality level, and the tool re-encodes it right in your browser. You see the original and compressed sizes side by side, the percentage saved, and a download link. Because all the work happens on your device, the image is never uploaded to a server, which keeps your files private and the result instant, even on a slow connection.
What is the Image Compressor?
Image compression reduces the number of bytes needed to store a picture. JPEG and WEBP use lossy compression: they throw away detail the human eye is unlikely to notice, such as subtle colour and brightness changes packed close together, and keep the rest. A quality setting, here a number from 0.1 to 1.0, controls how aggressively that happens. A higher quality keeps more detail and produces a larger file, while a lower quality discards more and produces a smaller file. The sweet spot for most photos sits around 0.7 to 0.85, where the file is much smaller but the loss is hard to spot at normal viewing size.
Under the hood this tool draws your image onto an HTML canvas and calls the browser method canvas.toBlob with your chosen format and quality. The browser re-encodes the pixels and hands back a compressed blob, which the tool measures and offers for download. Nothing is sent over the network, so there is no upload wait, no file size cap tied to a server plan, and no privacy concern about a third party storing your photo. This canvas approach means the dimensions stay the same: it is recompression, not resizing. If you also need fewer pixels, for example a 4000 px photo for a 1000 px slot on a page, resizing first will save far more than a quality change alone, because pixel count and quality both drive file size independently.
Format matters as much as quality. JPEG is the long-standing choice for photographs and is supported everywhere, but it cannot store transparency and it applies chroma subsampling, which softens fine colour detail slightly. WEBP is newer and usually produces a file 25 to 35% smaller than a JPEG at the same visual quality, and it does support transparency, though a small number of very old programs cannot open it. PNG, by contrast, is lossless and best for sharp-edged graphics, logos, icons and screenshots with flat colour or text, but it is a poor choice for photographs because it cannot discard detail and so stays large; a photographic PNG can be five to ten times bigger than an equivalent JPEG. This tool outputs JPEG or WEBP because those are the formats where lossy compression actually pays off.
When to use it
- Shrinking a large phone photo so it uploads quickly or fits an email or messaging attachment limit.
- Optimising images for a website or blog so pages load faster, rank better on Core Web Vitals, and use less bandwidth.
- Reducing a screenshot or product photo before attaching it to a support ticket, form, or marketplace listing.
- Converting a bulky PNG photo to a much smaller JPEG or WEBP while keeping it looking the same to the eye.
- Getting a profile picture, thumbnail, or hero image under a strict file size limit set by a platform or CMS.
- Freeing up phone or cloud storage space by compressing a batch of photos one at a time before archiving them.
How to use the Image Compressor
- Click Choose an image and select a JPG, PNG or WEBP from your device.
- Pick the output format: JPEG for the widest compatibility, WEBP for smaller files.
- Drag the quality slider (0.1 to 1.0); around 0.8 is a good starting point for most photos.
- Press Compress image to see the original and compressed sizes and the percentage saved.
- Click Download result to save the compressed file. Adjust the quality and recompress if you need it smaller or sharper.
Formula & method
Worked examples
A 2,000,000 byte (about 1.91 MB) JPEG photo is recompressed and the result is 600,000 bytes.
- difference = 2,000,000 minus 600,000 = 1,400,000 bytes
- percent saved = 1,400,000 divided by 2,000,000, times 100
- percent saved = 0.70 times 100 = 70%
Result: The file is 1,400,000 bytes smaller, a 70% reduction.
A 500 KB (512,000 byte) image is compressed down to 180 KB (184,320 bytes).
- difference = 512,000 minus 184,320 = 327,680 bytes
- percent saved = 327,680 divided by 512,000, times 100
- percent saved = 0.64 times 100 = 64%
Result: The file shrinks by 320 KB, a 64% reduction.
A 3.4 MB PNG screenshot with a transparent background is converted to WEBP at quality 0.8 and comes out at 410 KB.
- original = 3.4 MB = 3,565,158 bytes (approx)
- compressed = 410 KB = 419,840 bytes (approx)
- percent saved = (3,565,158 minus 419,840) divided by 3,565,158, times 100 = about 88%
Result: Switching format from PNG to WEBP and applying quality 0.8 cuts the file by roughly 88%, and WEBP keeps the transparency that JPEG would have discarded.
Rough guide to quality settings for a typical photograph
| Quality | Visual result | Best for |
|---|---|---|
| 0.9 to 1.0 | Near identical, little saving | Archiving, print, master copies |
| 0.75 to 0.85 | Very hard to tell apart | Websites, most everyday use |
| 0.5 to 0.7 | Slight softening on close look | Thumbnails, fast-loading pages |
| 0.1 to 0.4 | Visible blocky artefacts | Tiny previews where size is critical |
Choosing a format
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| JPEG | Lossy | No | Photographs, broad compatibility |
| WEBP | Lossy or lossless | Yes | Smaller files on the modern web |
| PNG | Lossless | Yes | Logos, screenshots, flat-colour graphics |
Common file size targets by use case
| Use case | Typical target | Why |
|---|---|---|
| Website hero or blog image | Under 200 KB | Keeps page load fast and helps Core Web Vitals |
| Email attachment | Under 10 to 25 MB total | Most providers reject or strip larger attachments |
| Social media post image | Under 1 MB | Platform re-compresses anyway, so smaller uploads look the same |
| Profile picture or avatar | Under 100 KB | Displayed small, so extra detail is wasted bytes |
| Marketplace or listing photo | Under 500 KB | Fast to load on mobile data for buyers |
Common mistakes to avoid
- Expecting compression to shrink the dimensions. This tool recompresses at the same pixel size, it does not resize. A 4000 px photo stays 4000 px wide. If you need it physically smaller, reduce the dimensions first, which usually saves far more than quality changes alone.
- Saving a transparent PNG as JPEG and getting a white background. JPEG cannot store transparency. When you convert a transparent image to JPEG the see-through areas are filled in (this tool uses white) so they do not turn black. Choose WEBP if you need to keep transparency.
- Recompressing an already-compressed JPEG repeatedly. Each lossy pass discards a little more detail, and the artefacts build up, a problem known as generation loss. Compress from the highest-quality original you have rather than re-saving the same JPEG again and again.
- Pushing quality so low the image looks blocky. Very low quality produces visible blocky artefacts and colour banding, especially in skies, gradients and skin tones. Drop the quality only until the saving is worthwhile and the image still looks acceptable at its display size.
- Compressing a screenshot or logo as JPEG instead of PNG or WEBP. JPEG is tuned for photographs with soft gradients, not flat colour and sharp text edges. Compressing a screenshot or logo as JPEG often produces fuzzy edges and colour bleed around text; PNG or lossless WEBP usually looks cleaner and can even be smaller for that kind of image.
- Assuming a bigger file always means a better-looking image. File size reflects how much data was kept, not how good the photo looks. A well-compressed 200 KB JPEG at the right resolution can look identical to a 2 MB original at normal viewing size; the extra bytes in the original are often invisible to the eye.
Glossary
- Lossy compression
- A method that permanently discards some image detail to make the file smaller. JPEG and WEBP are lossy.
- Lossless compression
- A method that shrinks a file without losing any detail, so it can be restored exactly. PNG and lossless WEBP are lossless.
- Quality
- A setting (here 0.1 to 1.0) that controls how much detail lossy compression keeps. Higher means better looking but larger.
- Artefact
- A visible flaw introduced by compression, such as blocky squares or colour banding, more common at low quality.
- Canvas
- An HTML element that holds pixels in the browser. This tool draws your image to a canvas and re-exports it to compress it.
- Compression ratio
- The relationship between the original size and the compressed size, often shown as a percentage saved.
- Chroma subsampling
- A technique JPEG uses to store colour information at lower detail than brightness, since the eye is less sensitive to colour changes, saving space.
- EXIF metadata
- Camera and location data (device model, date, sometimes GPS) embedded in a photo file. Re-encoding an image through canvas strips this metadata.
Frequently asked questions
How do I compress an image online for free?
Choose your image, pick JPEG or WEBP, set a quality (around 0.8 is a good start), and press Compress image. The tool re-encodes the picture in your browser and shows the new file size and the percentage saved, then offers a download link, with no account or payment needed.
Are my images uploaded to a server?
No. All compression happens locally in your browser using the canvas API. Your image never leaves your device, which keeps it private and makes the result instant even on a slow connection.
Will compressing reduce the image quality?
JPEG and WEBP are lossy, so some detail is discarded. At a quality of about 0.75 to 0.85 the loss is very hard to notice, while the file is much smaller. Lower quality saves more but eventually shows blocky artefacts.
How can I compress an image without losing noticeable quality?
Stay in the 0.75 to 0.9 quality range and start from the highest-quality original you have, not an already-compressed copy. WEBP at 0.8 typically looks the same as JPEG at 0.9 while producing a smaller file.
Does this tool resize the image as well as compress it?
No, it keeps the original pixel dimensions and only recompresses. If you need smaller dimensions too, resize the image first; reducing width and height usually saves far more bytes than changing quality alone.
Should I choose JPEG or WEBP?
WEBP usually produces a smaller file at the same visual quality and supports transparency, so it is the better pick for the modern web. Choose JPEG if you need the widest possible compatibility with older software or devices.
How do I get an image down to a specific size, like 100 KB?
Compress at a starting quality like 0.7, check the resulting size, then lower the quality slightly and recompress if it is still too big, or raise it slightly if there is room to spare. For very strict targets, resizing the dimensions down first makes it much easier to land under a small size such as 100 KB.
Why is my compressed file sometimes larger than the original?
If the original was already heavily compressed, re-encoding at a high quality can add bytes rather than remove them. Try a lower quality, or the other format, until the result is smaller than the original.
Does compressing an image remove EXIF metadata like GPS location?
Yes. Because the tool redraws the image onto a canvas and re-exports the pixels, camera and location metadata is not carried over to the compressed file. This is a useful side effect for privacy if you are sharing photos publicly.
Can I compress multiple images at once with this tool?
This tool compresses one image at a time so you can check the before and after result and adjust quality per image. Run it again for each additional photo; each compression takes only a second or two since everything happens in your browser.