Compress Image to 350kB

For viewing on a screen, yes, with one caveat about dimensions. At 350 kB a JPG holds roughly 1400 × 1000 px of a detailed photograph at good quality, and a WebP roughly 1700 × 1250 px, which fills a laptop screen or a tablet in landscape. On a 4K monitor the browser will upscale it slightly, so if your gallery is aimed at large-screen buyers consider a 2× version as WebP, or raise the target in the custom field.

350 kB is not a print file. Keep your RAW or full-resolution export for prints and licensing, and treat the compressed copy as the web version.

Use 350 kB whenever the image will be seen in a browser or an email client rather than printed. Squarespace recommends keeping each image at 500 kB or less so pages load quickly, and a median mobile inner page already spends about 350 kB on images in total, so a single file at this size is as heavy as a hero or gallery piece should go.

Go larger only for print, for archive copies, or when a platform explicitly asks for a bigger file. For a CMS that makes its own thumbnails, upload the 350 kB version rather than the original: the thumbnails look the same at small sizes, and you save upload time and storage.

Smaller than the numbers suggest. The extra 50 kB is about 17% more data, and at the same dimensions the quality search usually moves up only a few points. Where you notice it is in smooth areas: skies, skin, out-of-focus backgrounds and soft shadows can show faint banding or blockiness at 300 kB that softens or disappears at 350 kB.

Hard edges, text and logos change the least, because those areas are already crisp at the lower size; what the extra bytes mostly buy is smoother gradients. If your image is mainly edges and flat colour, 300 kB is a free saving. If it is mainly gradients, the extra bytes are worth keeping.

The quick chips cover the sizes that forms and platforms most often impose. Above 350 kB the number is usually your own choice, driven by page weight rather than an upload cap, so a fixed page for every value would add little.

If you do need 500 kB, 800 kB or 1.5 MB, open the [home compressor](/), type the number into the target field and switch the unit to MB if needed; the same quality search, resize options and before/after slider apply. For many files at once, the bulk compressor takes one target and an optional longest-side limit for up to 200 images and packs the results into a ZIP.

Mb2KbSizer is a free image and PDF compressor that runs inside your web browser. You pick a file, type the size you need, such as 100 kB, and it shrinks the file to land at or just under that number. Most people use it for upload forms that reject big files: exam registrations, passport and visa applications, job portals, bank KYC and college admissions. It is just as handy for lightening photos before you email them or put them on a website. There is a [single-image tool](/), a bulk compressor for up to 200 photos at once, and a PDF compressor, all built on the same no-upload principle.

Yes. Every tool on this site is free, and we intend to keep it that way. There is no sign-up, no premium tier, no daily quota and no watermark on the output. Compress one photo or three hundred; nothing counts against a limit. A few ads on the page pay for hosting. Because the heavy lifting happens on your own device rather than on our servers, each extra user costs us almost nothing, so there is no reason to charge. We do not sell an app, a plan or an API either, so you will never be nudged towards a paid version.

No installation is needed. Mb2KbSizer is a web page, so it works the moment it loads in current Chrome, Edge, Firefox, Safari or Samsung Internet on a phone, tablet or computer. Nothing is downloaded to your device except the page itself, and it does not ask for storage or camera permissions. If you use the tool often, you can add it to your phone's home screen from the browser menu and it will open like an app. It still needs an internet connection to load, though, so treat this as a shortcut rather than an offline program. There is no Play Store or App Store version.

Three steps, usually under a minute.

1. Add your photo. Drag it onto the upload box, tap browse to pick it from your gallery, or paste it from the clipboard with Ctrl/Cmd + V.
2. Set the target. Type a number and choose kB or MB, or tap a quick chip from 20 to 350 kB. On a preset page the field is already filled in. If a form demands exact pixel dimensions, set them in the resize option.
3. Press Compress, then Download. You get a before/after slider, the output dimensions, the quality used and the exact byte count, so you know it will pass before you submit it.

You can upload JPG, PNG, WebP, GIF (the first frame is used), BMP and AVIF, provided your browser can decode the file. HEIC photos from an iPhone open in Safari and other browsers with HEIC support; elsewhere the tool explains how to set the camera to Most Compatible so new shots are saved as JPG. Files up to 60 MB are accepted. For output, Auto gives a JPG in most cases and keeps WebP as WebP; you can also force JPG, WebP or PNG. PNG is lossless, so a PNG target is reached only by reducing dimensions, which is why JPG is the better pick for a small photo.

Strictly speaking, you never upload anything. When you choose a file, the browser reads it from your device and does the resizing and re-encoding in a background worker on that same device. No copy travels to our server or to anyone else's; the only thing our server sends you is the page. A useful side effect is that the browser rebuilds the image from its pixels alone, so EXIF data such as the camera model, the date taken and the GPS location is dropped from the output. That makes the compressed photo safer to share than the original you started with.

No. We have no image storage of any kind, because the file never reaches us in the first place. It sits in your browser's memory while you work, and the compressed version exists only on your device once you download it. Close or refresh the tab and both are gone. We keep no history, no gallery and no cache on our side, and we cannot see what you compress. Our web host records ordinary server logs, such as the time of a page visit and the browser used, but those cannot contain your pictures. For the full detail, read our privacy policy.