Learn · email signature glossary
TL;DR
Email signature image format is the choice of file type for the logo, headshot, icons, or banner in a signature, and the reliable options are exactly three: PNG, JPG, and GIF. PNG suits logos and icons because it is lossless, keeps sharp edges crisp, and supports transparency. JPG compresses photographs far more efficiently and is right for headshots and photographic banners. GIF exists for the rare animated banner. SVG is not dependably rendered by email clients despite being ideal for logos on the web, and WebP support remains too patchy to trust.
Re: In practice
Format mistakes produce the classic signature image failures. A logo saved as JPG gets compression artifacts around the letterforms and a solid white box where transparency should be, which turns ugly the moment a recipient views it in dark mode. A photo saved as PNG balloons to several hundred kilobytes for no visual gain, slowing message loads and irritating spam filters. An SVG logo simply does not appear for many recipients. The working rules: transparent PNG for anything with hard edges or transparency needs, JPG at reasonable compression for anything photographic, keep each file under about 100 KB, and export at twice the displayed dimensions so images stay sharp on high-density screens. Set explicit width and height in the HTML regardless of format, since some clients otherwise render images at native size.
Fwd: Worth a look
dark mode signature issues
Dark mode inverts email backgrounds and can make logos and text in signatures unreadable. Learn what changes and how to design around it.
brand colors in signatures
Email signature colors are the text, accent, and link hues in your sign-off, set as inline hex values and chosen to survive dark mode inversion.
what a signature generator does
An email signature generator is a tool that turns your details into ready-to-paste, email-safe HTML, sparing you from hand-coding tables.
signature logo specs
An email signature logo is your company mark embedded in the signature block. Learn correct sizing, file format, and hosting for email clients.
signature headshot
An email signature photo is a small headshot beside your contact details that puts a face to your name. See sizing, format, and when to use one.
signatures on mobile devices
A mobile email signature is what appears under messages sent from your phone, set separately per app and best kept short and narrow.
Free generator, no account required. Works in Gmail, Outlook, and Apple Mail.
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