Compress images online without uploading them
Photos from modern phones and cameras are huge. A single picture can weigh 5 MB or more, which is far over the limit of many email providers, job application portals, online forms and content management systems. This free image compressor lets you reduce JPG, PNG and WebP file size right in your browser. Unlike most online compressors, nothing is sent to a server: your pictures are processed on your own device and disappear when you close the tab.
You can compress to a specific target size, for example "under 200 KB", or simply pick a quality level and a maximum width. The tool works through several rounds automatically: it lowers quality step by step with a binary search, and if the quality floor is reached before your target, it scales the image down slightly and tries again. The result is the best-looking picture that still fits the limit you chose.
How to compress an image
- Drag your pictures onto the drop area above, or click Choose images and select one or many files from your computer or phone.
- Choose a preset such as email attachment, or set the output format, target size in KB and maximum width and height yourself.
- Press Compress images. Each file shows its old size, new size and new dimensions so you can see exactly what you saved.
- If you are not happy, change the settings and press the button again. The original file is reused every time, so quality is never lost by repeating the process.
- Download files one by one or use Download all. The file name stays the same; only the extension changes if you switched format.
Why use this compressor?
- Private by design. The images never leave your device. There is no upload step, so there is nothing to intercept, store or sell.
- Target size control. Most tools only offer a vague quality slider. Here you can type a size in kilobytes and let the tool find the right quality for you.
- Batch processing. Add dozens of images at once and process them with one click, with a progress bar and per-file results.
- No sign-up or limits. No daily quota, no watermark, no email address required.
- Works offline. After the first visit the page can be installed as an app and used without a connection.
- Phone friendly. The interface is designed to work on a 360 px wide screen, with large buttons and keyboard support.
JPG, PNG or WebP: choosing the right format
The best way to make an image smaller is to choose the right format before touching any slider. JPG is a lossy format designed for photographs. It throws away detail that the human eye barely notices and produces small files. PNG is lossless, so it keeps every pixel and supports transparency, but photographs saved as PNG are often five to ten times larger than the same picture saved as JPG. WebP is a newer format developed for the web that usually beats JPG by a quarter or more at the same visual quality.
A practical rule: use JPG when you share photos, use PNG for logos, screenshots and diagrams, and use WebP when you publish images on your own website. If you turn a PNG with transparent areas into a JPG, the transparent parts are filled with white, because JPG has no transparency.
Common situations and settings that work
Email attachments are the classic example. Many mail servers reject messages above 20 to 25 MB in total, and sending eight raw phone photos can hit that limit instantly. Resizing to about 1600 pixels on the long edge and compressing to roughly 200 KB each keeps every picture crisp on screen while shrinking the whole message to a couple of megabytes.
Online application forms and government or university portals often cap uploads at a fixed size such as 100 KB, 500 KB or 1 MB. Enter that number as the target size and the tool does the arithmetic for you. For profile pictures, 800 by 800 pixels at 100 KB is more than enough for almost every platform. For blog posts and online stores, images around 1200 to 2000 pixels wide and under 300 KB help pages load faster, which improves both visitor experience and search rankings.
Printing is the exception. If you plan to print a photo, keep the full resolution and a high quality value such as 90 to 95 percent, because shrinking pixels cannot be undone. Always keep your original files, and treat compressed copies as the versions you share.
How the compression works
Your browser decodes the picture into a bitmap, draws it onto a canvas at the requested size, and then re-encodes it with the format and quality you picked. For JPG and WebP the tool performs a binary search over the quality value: it tries a middle quality, checks the resulting file size, and moves up or down until it finds the highest quality that fits your target. This is the same technique image professionals use by hand, only automated. Orientation data from phone photos is respected, so pictures taken in portrait mode do not turn sideways.
Because everything relies on the built-in browser engine, there is no extra library to download and the tool starts instantly. It also means the privacy promise is simple to verify: open your browser's network panel while compressing and you will see that no request carries your image anywhere.
Frequently asked questions
Are my photos uploaded to a server?
No. Compression happens in your browser using the built-in canvas feature. Once the page has loaded you can switch off your internet connection and the tool still works. There is no upload, no account and no tracking of your files, which makes it a safe choice for ID scans, contracts and family pictures.
What does "could not reach target" mean?
You asked for a target size such as 100 KB, and the tool tried lowering the quality down to 30% and shrinking the dimensions up to twelve times without getting under it. That usually happens with very detailed images saved as PNG. Raise the target, choose JPG or WebP, or lower the maximum width and height and run it again.
How many images can I add, and is there a size limit?
There is no artificial limit. Your device memory is the real boundary: a modern laptop handles hundreds of 12-megapixel photos without trouble, while an older phone may struggle with many large files at once. Files over 50 MB trigger a warning, and if the tab runs out of memory, process the photos in smaller batches.
Will the image get blurry or lose quality?
If you do not set a target size, only the quality slider is applied, and at 85% most people cannot tell the difference from the original. With a strict target the tool lowers quality gradually and only then reduces the pixel dimensions, so you get the sharpest picture that still fits your limit.
JPG, PNG or WebP: which should I choose?
Pick JPG for photographs, because it gives the smallest files and every program opens it. Pick PNG for screenshots, logos and graphics with sharp edges or transparency, accepting larger files. Pick WebP for websites, where it is usually 25 to 35 percent smaller than JPG at similar quality; modern browsers and apps support it, but a few old programs do not.
Does it work on iPhone and Android?
Yes. Open this page in Safari, Chrome or any modern mobile browser, tap Choose images and select photos from your gallery or take a new one. HEIC files from an iPhone are not readable by browsers; set the camera to "Most Compatible" or convert them to JPG first.
Is the original file changed?
Never. Your original stays exactly where it is. The tool reads it, creates a new compressed copy in memory and offers it as a download. You can change the settings and run the compression again as often as you like, and each run starts from the original so quality does not degrade with repeated attempts.
Is it really free?
Yes. There are no daily limits, no watermarks, no premium plan and no sign-up. The site is supported by a small number of ads placed away from the buttons, and you never have to see a paywall to download your result.
Related tools
Need images optimized in bulk, a faster online store or custom software? The team at Bilişim Ajans can help.