Compression Settings for Email, Web and Uploads
Limits differ: email is often 10-25MB, web pages care about transfer bytes, and ecommerce/ID uploads often impose dimensions and KB limits. Confirm the target limit, then try dimension/quality settings instead of blindly minimizing.
Starting points
Email attachments: longest side 1600px, JPEG 80%.
Web images: longest side 1600-2000px, WebP/JPEG 80-85%.
Avatars/thumbnails: 256-512px, JPEG/WebP 85%.
Text screenshots: PNG or WebP, keep quality and crop first.
Checklist
The target platform opens the output format.
The file is under the limit and text is still readable.
Transparency was not filled white/black.
Keep the original until the output is confirmed.
FAQ
What size for email attachments?
Check the mailbox limit; 10-25MB is common, and 1-3MB per image is safer.
Must web images be WebP?
Not necessarily; WebP is often smaller, but JPEG/PNG are more compatible.
Sources
Related calculators
Image CompressorChoose a JPG/PNG/WebP, set quality and max width, compress locally and compare before/after size for uploads, email and web images.More guides
Image Compression Basics: Quality, Size and FormatRead guide继续读
按顺序读，或跳到同主题的其他指南。