Start with JPG or WebP at about 80% quality. If your email provider still rejects the attachment, choose a target size or reduce the image's long edge. Keep a separate original.
Measure before changing pixels
A large file is not always a large-looking image. Detailed photos and PNG screenshots may use many bytes even at modest dimensions. Add the file to Image Compressor and note both its file size and pixel dimensions before choosing a target.
Compress once and compare
Use the default 80% quality as a starting point. Compare fine text, faces and gradients in the before/after preview. If the file meets the attachment limit and looks clean, download it without resizing.
Use an exact target when required
Select 200 KB, 500 KB, 1 MB or 2 MB only when a mail system gives a strict limit. The tool lowers encoding quality first and may proportionally reduce dimensions if quality alone cannot reach that target. It labels resized results.
Handle several attachments together
Add up to 20 images, apply one setting and download the completed results as a ZIP. Extract the ZIP before attaching individual files. The browser processes the batch locally, so personal images do not travel to a conversion server.
Resize for on-screen viewing
If recipients only need to view a photo on a phone or laptop, a long edge around 1600-2400 pixels is often sufficient. Use Image Resizer's long-edge mode, then compress the resized copy if necessary.