Signature design

Email signature dimensions: width, logo, and photo

A signature is a footer, and a footer has to stay smaller than the message above it. The sizes that hold up are a width near 420px, never past 600px, and a logo or photo between 32px and 96px.

Width: About 420px for a full signature. Stay under 600px, which is a typical phone message column.
Logo: 32–96px. 32px is the quiet end, 64px is the usual size beside the name, 96px is a large mark. How the mark is placed.
Photo: 40px on the name line, 64px beside the name, 96px as a portrait. How the headshot is placed.
File: Export the image near 200px. PNG for a logo, JPG or PNG for a photo. If it is too heavy, Gmail will ask you to resize it.

Logo and photo, drawn at real size.

Each mark is the size it will actually have in the signature. 32px is a quiet avatar, 40px sits on the name line, and 64px is the usual logo beside the name. 68px is a photo with a ring, and 96px is a portrait. That is the useful range: under 32px the mark disappears, and over 96px it starts to compete with the message.

32pxAvatar

40pxBadge photo

64pxDefault logo

68pxRing

96pxPortrait