PRACTICAL HOW-TO

How to Prepare Images for Email

Email attachment limits vary by provider, account and recipient system. A message may also grow larger after attachments are encoded, so a file that appears to be just under a limit may still fail to send.

Before you start: Keep an untouched copy of the source file. Always follow the destination website or app’s exact upload requirements if they differ from this general guide.

Choose a sensible pixel size

For a photo that only needs to be viewed in an email, a few thousand pixels on the long edge is often more than enough. For a small inline image, the needed dimensions may be much smaller. If the recipient must zoom into fine detail, keep a higher-resolution copy.

Compress photos; preserve important graphics

JPG is usually practical for photographic images. PNG is useful for transparent graphics, sharp diagrams and screenshots with small text. WebP can be efficient but may not be accepted by every recipient workflow, so confirm compatibility before using it for an attachment.

Test the actual attachment size

If the message must stay below a strict limit, leave a margin rather than aiming exactly at the provider’s maximum. A 9 MB attachment can create a larger email message after encoding. When the attachment remains too large, resize first and then compress.

When a link is better

For many high-resolution photos or files that must retain original quality, use a trusted file-sharing method if the recipient can access it. Confirm permissions and avoid sharing sensitive images through a public link.

Check before sending

Open the exported copy, confirm that the correct image is attached, and make sure text or small details remain readable. Keep the original in case the recipient later needs a higher-quality version.

Quick decision guide

File exceeds a KB/MB limit: compress the image; resize first if its dimensions are larger than needed.
Pixel dimensions are wrong: resize or crop, then recheck file size.
Format is rejected: convert to a format the destination explicitly supports.
Visual quality changed: compare the output with the original and try a less aggressive setting.

Related tools and explanations

Compress to a target size →Resize Image →Check image size →Image file size for email →

This guide explains general image-handling principles. Specific requirements vary by website, device, browser and export settings; verify the final file before using it.