Email attachments
Resize Image to 100 KB
Preset and ready: drop a file and the output lands under 100 KB as JPEG — processed entirely in your browser.
Drop your image here or browse
JPEG, PNG, WebP — everything stays on your device
Why this exact limit matters
Email attachments live by the mailbox’s rules, and "100 KB" is the quiet sweet spot: small enough that a dozen of them still fit the strictest corporate gateway, large enough that a photo arrives looking like a photo. Resizing for email is really a display decision — mail clients show images around 600–800 pixels wide — so cap the frame there and let the KB ceiling handle the rest.
Shrinking attachments to a stated size keeps mail deliverable without forcing you to learn a photo editor just to send a picture. 100 KB is a moderate limit, common for application portals, and this page is preset to exactly that ceiling.
How to compress to 100 KB
- Drop your image into the box above — it stays on your device.
- Confirm the target: under 100 KB as JPEG.
- The MozJPEG encoder searches its quality range so the JPEG output lands just under your limit. Dimensions are left at their original size unless the target demands otherwise.
- Preview the result, compare it with the original if you want, and download — the filename carries its actual size.
Tip: If you attach photos regularly, compress before attaching rather than relying on the mail client's "large attachments" link — those links expire, while a small attachment is a real attachment.
Measured: the email-sized version of a real photo
Our 914 KB portrait test file with an email-realistic 800×1000 frame and a 100 KB ceiling:
Source file
914 KB
1500×1800 JPEG
Output
95.5 KB
9.6× smaller
Frame
800×960
inbox display size
Quality setting
q56
solid mid-range
Quality 56 at email display size is visually indistinguishable from the original when the message is opened — recipients see a photo, not a compression artifact. The 9× shrink also matters for people on metered or slow connections: the same attachment, a ninth of the bytes.
Frequently asked questions
Why not let my mail client’s "large attachment" link handle it?
Those links expire, get blocked by corporate filters, and force the recipient to leave their inbox. A 100 KB attachment is a real attachment — it arrives with the message and stays there.
Is 100 KB overkill if my mail system allows 25 MB?
Your system’s ceiling is not the recipient’s — mixed gateways along the route enforce their own limits, and full-size phone photos (3–8 MB) trip them regularly. Small attachments deliver more reliably than big ones.
Should I resize or just compress for email?
Both, via one decision: cap the frame at display size (600–800 px wide is plenty) and the compression follows naturally. Resizing without a byte target still yields multi-megabyte files; compressing without a frame wastes budget on invisible pixels.
Will the recipient see a quality difference?
For photos shared to be looked at on a screen, the output of this tool at typical email limits is visually indistinguishable from the original. The comparison view shows both images side by side so you can judge for yourself.
How does the tool hit the exact JPEG size?
It encodes your image with the MozJPEG encoder several times, binary-searching the quality setting until the output lands just under your limit — then keeps that best result.
Do I need an account or app install?
No account, no install, no watermark. The page you are on is the whole tool.