Email Attachment Optimizer
Prepare PDFs and JPG, PNG or WebP images together. Choose a sending target, check the final total and download the files.
The ZIP has its own size; check it in your mail app before sending.
Images are processed in this browser. PDFs that need compression use temporary server processing and your daily PDF allowance. Files already within their allocated target are kept unchanged. How file processing works
Stopping the batch prevents further files from starting. A PDF job already submitted to the server may continue; normal job expiry and cleanup still apply.
One target for the whole message
Attachments share the selected byte budget. Larger files receive a larger share. Email encoding can increase the message size, so the default targets leave room below the documented provider limits. The displayed message estimate includes base64 encoding, line breaks and a header allowance; it is not a measurement of the email your mail app will send.
Review before sending
The final total uses the actual downloaded-file sizes, not a predicted saving. An attachment that cannot reach its allocated target is shown as over target. Review text and image detail, especially with Smaller files. A result within this target is not a guarantee of delivery: recipients, account policies and message content can impose other limits.
Keep a useful original
Quality and byte size are different goals. The original is kept if it already fits its share or compression would not improve it. Optimized PNG images remain PNG, so transparency and file compatibility are not silently changed; this can limit achievable savings. Re-encoded images do not retain the original metadata. This workflow is not a substitute for a metadata inspection.
Which PDFs can be compressed?
Unsigned, unencrypted PDFs with up to 200 pages and no interactive annotations or fields can be compressed here. Interactive documents may be kept unchanged when they already fit, but are not sent for compression. Images and PDFs are processed one at a time. A PDF result is parsed again and checked for the original page count before a download is offered.
Provider limits
Provider limits can change. Desktop Outlook here means an internet email account, not every Exchange or organization configuration.
