Most "image too large" errors come with a number attached: an application form that stops at 100 KB, an email that bounces over a few megabytes, a chat app that re-compresses anything big on its own terms. These tools are built around that number. Pick the target, drop your images in, and each one is compressed until it fits — entirely inside your browser, so nothing is uploaded.
Which one to use
| Your situation | Tool |
|---|---|
| A signature or exam photo with a range like 10–20 KB or 20–50 KB | Compress to 20KB or 50KB (they also enforce the minimum) |
| A file that is too small for the form’s minimum, and the pixel size must not change | Increase Image Size in KB |
| An application, visa or government form with a strict KB limit | Compress to 100KB or 200KB |
| Not sure whether the form means 1,000 or 1,024 bytes per KB, or why Windows shows a different number | MB to KB Converter — both answers, plus what Windows will show |
| A limit that isn't one of the round numbers | Compress to Target Size |
| Email attachments, forums and listings | Compress to 500KB or 1MB |
| Sending photos in WhatsApp | Compress for WhatsApp |
| Sharing images in Discord | Compress for Discord |
| A PNG screenshot, logo or icon that must stay a PNG, with its transparent background | Compress PNG — a Chrome screenshot went from 87 KB to 40 KB at 256 colours |
| An animated GIF that is too big for an emoji, a chat or a page | Compress GIF — keeps the animation |
How compressing to a target size works
Lossy formats such as JPG and WebP can store the same picture at many different quality levels, and each level produces a different file size. Compressing to a target means the tool adjusts that level for you until the result lands under your limit, instead of you nudging a quality slider, exporting, checking the size and trying again. If an image is already under the target, it is left as it is rather than re-encoded for no reason.
The trade-off is real. A 4 MB phone photo squeezed down to 100 KB will lose visible fine detail. For a form that only needs a recognisable photo, that is exactly what you want. For a photo you care about, keep the original and compress a copy.
Chat apps are a different problem
WhatsApp compresses the photos you send on its own terms, and very wide images are scaled down before they are sent. Compressing first puts the quality decision in your hands — and when you need the full-quality original to arrive, sending the image as a document skips WhatsApp's compression altogether. Discord raised its free upload limit to 20 MB in 2026, so there the reason to compress is speed: smaller files upload faster on mobile data and preview more cleanly in the channel.
How small can a photo actually get?
We measured this rather than guessing. A 4608×3456 photograph, 9.2 MB as it came off the camera, compressed at a fixed quality of 80:
| Width | File size | Good for |
|---|---|---|
| 4608 px (original) | 2,999 KB | Printing large, archiving |
| 2048 px | 647 KB | Anything on screen, most uploads |
| 1280 px | 259 KB | Email, chat, web pages |
| 800 px | 103 KB | Forms with a 100 KB limit |
The lesson that surprises most people: resizing saves far more than the quality slider. Dropping quality from 80 to 30 on the full-size photo saved 1.7 MB and visibly damaged it; resizing to 2048 px at the same quality saved 2.35 MB and looked untouched on any screen. The full set of measurements, including why exporting at “quality 100” produces a file larger than the original, is in how to make a photo smaller.
Which of these tools is which
- Target size takes any number you type and searches for the settings that land just under it.
- The fixed-size tools (100 KB, 200 KB, 500 KB, 1 MB) are the same engine with the number pre-set and the page written around that specific limit — what usually enforces it, and what quality to expect at that size.
- The platform tools (WhatsApp, Discord) target what the service accepts and explain what it does to your file afterwards.
- Compress GIF is a different job entirely: it keeps the animation and re-encodes frames, rather than treating the file as one still image.
One thing none of them can do: recover detail that compression has already removed. Keep the original if you might need it later — a compressed copy is a one-way trip.
Nothing leaves your device
Every tool on this page runs locally in your browser. Your photos are not uploaded, queued or stored anywhere, there is no account to create, and there is no daily limit on how many images you compress.