Image Compressor
Shrink photos while keeping them sharp — to an exact size like 100 KB if you need one.
How to Use
- Upload your images — drag & drop, browse, or import straight from Google Drive, Dropbox or Yandex Disk. Batch up to 20 files at once.
- Choose a compression mode: Presets for one-click platform profiles (Instagram, web, marketplaces), Manual to fine-tune the quality slider with a live size estimate, or Target size to compress to an exact file size like 100 KB.
- Pick the output format (or leave Auto). WebP gives the smallest files; keep JPG or PNG when compatibility matters. Auto keeps the original format and turns PNG into WebP.
- Click Compress (or press Ctrl+Enter). Everything runs locally in your browser — your photos never leave your device.
- Compare before/after with the slider and see how many KB or MB you saved on each image.
- Download a single image or all of them as a ZIP, or send the result to another tool, such as the resizer or the converter.
Optimization Guide & Technical Info
About Image Compressor
In today's digital landscape, image optimization has become a critical factor for website performance and user experience. Our Intelligent Image Compressor tool addresses these challenges by providing a secure, browser-native solution for reducing image file sizes while strictly preserving the original format and transparency.
The tool leverages a floating algorithm to analyze each image in a batch independently. By applying a logarithmic correlation between file size and compression aggression, it ensures that small, high-quality images aren't over-processed, while large, heavy photographs receive significant optimization. This 'Smart Averaging' approach delivers professional results without the need for manual adjustment of every single file.
Privacy is at the heart of our platform. Unlike server-based solutions, our tool processes everything locally using the HTML5 Canvas API, so your images never leave the device. How much smaller a file gets depends on the picture — try it on yours.
Compress Images for Specific Platforms
WordPress & CMS Optimization
WordPress sites often slow down because of uncompressed images in the media library. The tool batch-compresses files before you add them to your CMS. WebP at quality 80 is a sensible start for featured images — check the page in PageSpeed Insights before and after. Works with any CMS: Shopify, Wix, Squarespace, Ghost, Joomla, Drupal.
Chat apps: Discord, Telegram, WhatsApp
Chat apps cap the size of an upload, and the cap depends on the app and on your plan — and it changes. Look up the current limit in the app’s help, then use Target size mode with a small margin below it.
Etsy, eBay & Amazon Product Photos
Marketplaces set their own limits for product photos, and they change — check your marketplace’s seller help. Use Target size mode to fit under the limit, or quality 85 to keep fine detail.
Google Slides & PowerPoint Presentations
Full-resolution photos make .pptx files heavy and slow to open. Compress images before inserting them — JPEG at quality 80 is a sensible start — and check the deck’s size before sending it.
Technical Deep Dive: Format Comparison
JPEG vs WebP vs AVIF — When to Use Each
| Format | Description |
|---|---|
| JPEG (1992) | Universal standard — every browser, app, and device supports it. Best for: maximum compatibility, email attachments, legacy systems. |
| WebP (2010, Google) | Compresses better than JPEG at the same visual quality and supports transparency and animation. In our own test WebP brought PNG screenshots to about half their size. Best for: web images, social media, any modern website. |
| AVIF (2019, AOM) | Usually compresses further than WebP and keeps 10/12-bit color for HDR. Encoding is slower, and fewer programs open it. Best for: large website images and photography where every kilobyte counts. |
| PNG | Essential for lossless graphics and transparency. Our tool preserves PNG integrity while finding internal optimization opportunities. |
Optimizing Images for Core Web Vitals
Core Web Vitals are part of how Google judges page experience. Largest Contentful Paint (LCP) measures how fast the biggest visible element loads — usually an image; Google publishes the current thresholds on web.dev. For images that means:
- Hero image: usually the heaviest file on the page — compress it first and serve WebP or AVIF
- Above the fold: everything visible without scrolling loads first, so the total size of those images matters most
- Below the fold: lazy-loaded images arrive later, but each one still costs data on a phone
- Thumbnails and icons: shrink the dimensions first — resizing saves more than any quality setting
The compressor shows exact file sizes before and after, so you can see what each change saves before deploying.
Formulas and Algorithms
Understanding the mathematical principles behind image compression helps you make informed decisions about quality settings and expected outcomes.
Ratio = (Original - Compressed) / Original × 100% Quantifies how much smaller the output file is compared to the original.
File Size ≈ Base Size × e^(k × q) For JPG and WebP the file grows roughly exponentially with the quality factor q (0.0 to 1.0): the last few points of quality cost the most bytes.
K = min(W_max / W_orig, H_max / H_orig)
W_new = W_orig × K Maintains aspect ratio using proportional scaling.
P(x,y) = Σ(i,j) w(i,j) × I(x+i, y+j) HTML5 Canvas uses bilinear or bicubic interpolation for resampling pixels.
BPP = (Size in Bytes × 8) / (Width × Height) Measures efficiency: the fewer bits per pixel at the same look, the better the compression.
Real-World Use Cases
E-commerce Product Catalogs
An online shop uploads product photos straight from the camera. Target-size mode brings each one under the marketplace's limit, and any drop in resolution is reported, not hidden.
News & Media Publishing
A newsroom compresses photos before they go on the page, so a slow connection still shows the picture quickly.
Mobile App Development
An app bundles destination photos, and every megabyte is a download the user waits for.
Social Media Content
A small agency prepares images for several networks every day and needs them under upload limits without surprises.
Email Marketing
Product images make a newsletter heavy. A 50 KB target keeps each one light.
Frequently Asked Questions
Q: What's the difference between lossy and lossless compression?
A: Lossy compression (JPEG, WebP) discards image data the eye barely notices, so files shrink a lot — right for photos. Lossless (PNG) keeps every pixel, so the saving is smaller but the picture stays exactly the same — right for logos and screenshots.
Q: Is my image data sent to any server?
A: No. All operations occur in your browser using JavaScript. Your images never leave your device, ensuring complete privacy.
Q: What quality setting should I use for web images?
A: 75–85% provides the optimal balance. Hero images should use 85–90%, while thumbnails can go down to 65–75%.
Q: Can I compress images without losing transparency?
A: Yes. Use PNG or WebP output formats. JPEG does not support transparency and will add a solid background.
Q: Can I compress images to a specific file size?
A: Yes. Switch to 'Target' mode and enter your desired KB. The tool uses binary search to find the quality level that hits your target size.
Q: How do I fit an image under a chat app’s upload limit?
A: Look up the app’s current limit — it depends on the app and your plan and changes over time. Then use Target size mode and set a value a little below it; the tool finds the highest quality that fits.
Q: What is the difference between AVIF and WebP?
A: AVIF usually makes smaller files than WebP at the same visual quality, but encoding is slower and fewer programs open it. If the image must open everywhere, WebP or JPG is the safer choice.
Q: How do I batch compress multiple images at once?
A: Select or drop up to 20 files at once. They are processed one after another, and you can download them all as a single ZIP.
Q: Does compressing an image multiple times hurt quality?
A: Yes. Every lossy compression cycle adds artifacts. It is always better to compress from the high-quality original file.
Q: How does image compression affect SEO?
A: Lighter images load faster, and Google counts page experience — Core Web Vitals included — among its ranking signals. A heavy hero image is the most common reason a page scores poorly.
Q: Should I resize images before compressing?
A: Yes! Reducing pixel dimensions saves far more space than compression alone. Our tool allows you to do both simultaneously.
Q: What is the best format for website images?
A: WebP is the safe default: it compresses well and modern browsers open it. AVIF can be smaller still — check that your site's platform accepts it.
Q: How to optimize WordPress images without plugins?
A: Compress them here to WebP at 80% before uploading. This keeps your media library light and your site lightning fast.
Q: Can I use this tool offline?
A: Yes! After the page loads, the compression engine works locally without needing an active internet connection.
Q: Does this tool strip EXIF metadata?
A: Yes. The image is redrawn and re-encoded, so EXIF metadata — camera, date, location — is dropped. That saves a little space and keeps your location private.
Q: How do I compress an image to 100 KB?
A: Open Target size mode, type 100 and choose KB (or tap the 100 KB chip). Each image runs a binary quality search to land just under 100 KB — the same works for 20 KB, 50 KB, 200 KB or 500 KB.
Q: How do I reduce image size in KB for a form or job portal?
A: Many forms and government portals cap uploads at 100 KB or 200 KB. Use Target size mode, enter the limit, and download a file that fits — no quality guesswork.
Q: How can I compress a passport or ID photo to the required size?
A: Switch to Target size mode and enter the exact KB your application asks for. The tool keeps the highest possible quality while staying under the limit.
Q: Can I reduce a photo from MB to KB?
A: Yes. Set the target in KB (for example 200 KB) and a multi-megabyte photo is compressed down to that size automatically.
Q: How do I compress a PNG or JPG online without installing software?
A: This free compressor runs entirely in your browser — no signup and nothing is uploaded to a server. It works on Windows, Mac, Android and iPhone.