Oversized images slow down websites, fail email size limits, and make chats crawl. Compressing shrinks the file so it loads fast and fits where you need it, and doing it in the browser means nothing ever gets uploaded.
ThothBox's Compress Image tool reduces file size right on your device. It handles common formats like JPG, PNG, and WebP, and you can control how much size you trade for quality.
JPG files are built for photographs and compress heavily with little visible harm, which makes them the easiest to slim down. PNG files are lossless and better for graphics and screenshots, but they compress much less — a PNG will almost always stay larger than a JPG of the same picture.
If a PNG is too heavy, converting it to JPG is often the fastest way to a small file. For images that need transparency or crisp text, keep PNG and settle for gentler gains.
The single biggest lever on file size is pixel count. An image with a million pixels is already heavy before compression, so resize to the size you actually use first, then compress the result. Combining the two routinely cuts files by far more than either step alone.
For email, a thin strip of resolution at a modest quality setting fits almost any limit. For the web, matching your dimensions to the display size and applying a mild compression keeps pages fast without obvious quality loss.
Use the Compress Image tool — it is free, needs no account, and works right in your browser.
No. Compression happens locally, and your image never leaves your device.
A gentle setting keeps the image looking sharp, with most of the size taken out of the file.
Resize the image small enough to fit the limit, then compress with a light-to-moderate setting.
Yes, the tool works in any browser on a phone or tablet.