Compress Images for Email Attachments
Most email providers limit attachments to 20-25 MB, and large images can clog your recipients inbox. A single uncompressed photo from a modern smartphone can easily exceed 5 MB. Here is how to compress your images so they send quickly, load fast, and still look great.
Understanding email size limits
Gmail caps attachments at 25 MB, Outlook at 20 MB, and Yahoo at 25 MB. Keep in mind that base64 encoding inflates file size by about 33% during transmission. As a rule of thumb, aim for individual images under 1 MB and total attachments under 10 MB to ensure reliable delivery across all providers.
Resize before compressing
The most effective way to reduce file size is to resize the image dimensions. A 4000x3000 pixel photo is far larger than what anyone needs for email viewing. Resizing to 1600x1200 pixels cuts the data by 75% before compression even begins. For most email purposes, 1200 pixels on the longest edge is more than sufficient.
Choose the right format
Convert to JPG at quality 80 for photographs. This typically produces files under 500 KB for a 1200-pixel-wide image. For screenshots or images with text, PNG is better but larger. Avoid sending BMP or TIFF files by email, as they are uncompressed and unnecessarily large.
Batch compress with SquishConvert
Upload multiple images to SquishConvert, set your desired format and quality, and download all compressed versions at once. No software to install, works from any device. Perfect for quickly preparing a batch of photos to send by email.
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