Make images smaller (JPG/WebP) with a quality slider — ideal for emailing or uploading.
Anyone trying to reduce photo size for email runs into the same wall: mail servers cap attachments, usually at 10 MB on business accounts and 25 MB on the big free services. A shot from a recent phone is 4 to 8 MB, so three of them already fill that up. At 80 percent quality the same photo usually drops below 500 KB, and on a screen you can barely tell. You can load several images at once; with more than one, they come back as a zip. If the whole set stays too heavy, a download link travels more easily than an attachment.
At the same quality, WebP is typically a quarter to a third smaller than JPG, and every browser from the last few years displays it without fuss. For anything going on a website it is the better pick: the page loads noticeably faster. The moment the file leaves your hands, JPG is the safer bet; older photo software, upload forms on webshops and portals, and print suppliers still often reject a .webp. Rule of thumb: WebP for your own site, JPG for anything you send on. On a screenshot with text, WebP holds sharp edges better than a JPG pushed far down.
The slider runs from 30 to 95 percent and starts at 80; between 75 and 85 you rarely see a difference from the original on screen. Below 60, blotches show up in flat areas: sky, a wall, a plain backdrop. A photo full of detail, grass or foliage, takes more punishment. Compression is irreversible, so work from the original rather than a copy that has already been through a round; the damage stacks. That original stays on your computer, by the way, since the work happens in your browser. One last thing: the pixel dimensions do not change; for that, use Resize.