Quick answer
Local Email attachments tools are more private and work offline; online tools save installation but files leave your device. Mailboxes often limit 10-25MB; 1-3MB per image is safer. Resize before lowering quality.
Why it matters
Use local for sensitive files; online is fine for small temporary ones.
Recipient clients may compress again.
Step by step
- Back up the original; never overwrite the only copy.
- Confirm the target platform's format, dimensions and size limit.
- Cap the longest side first, then quality; change one variable at a time.
- Compare size and sharpness after compressing, and step back one setting if needed.
- Keep the original until the output is confirmed.
Common mistakes
- Chasing the smallest file and blurring text/edges.
- Converting transparent PNG to JPEG, turning transparency white or black.
- Recompressing the same file and accumulating loss.
- Overwriting the original, so a bad result cannot be undone.
Checklist
- Original backed up.
- Output format/dimensions/size meet the platform.
- Text is readable and transparency is correct.
- Verified in the real page/email/upload field.
- Original kept until confirmed.
Key facts
- Recipient clients may compress again.
- Compress each image before zipping several.
FAQ
Local or online tools for Email attachments?
Local Email attachments tools are more private and work offline; online tools save installation but files leave your device. Mailboxes often limit 10-25MB; 1-3MB per image is safer. Resize before lowering quality.
How long does it take?
Usually 1-3 minutes; for intermittent issues, run 30 seconds and retest elsewhere.
Is data uploaded?
Runs locally and does not upload video/audio; extensions may still read the page.
Source: Gmail attachment limits