Shrink the file with a live quality preview, so you can see the moment it starts to hurt. Free, no signup, and the file never leaves your device.
A 9 MB photo and a 2 MB attachment limit.
Image Compressor is one of 22 free browser tools on IMGX Studio, filed under Convert & compress. It runs entirely on your own device: the image is read in the browser, processed there, and never uploaded to a server, so there is nothing to delete afterwards and no account to create.
Open the tool, drop in an image, adjust the settings, and download the result. It works on desktop and mobile, there is no watermark, and there is no limit on how many times you use it.