Prepare a signature-sized derivative instead of inserting the full-resolution headshot directly. Set its display size in the Outlook signature workflow, then inspect an actual received email. The editor preview does not establish how another client will render the image or whether that client will expose it as an attachment.
Define the portrait's role
The portrait should help identify the sender without dominating the message. Keep the sender's name, role and contact information as ordinary text. If images are blocked, the recipient should still know who wrote the email and how to reply or visit the intended site.
Start from the approved headshot and make a dedicated crop with a clear face and minimal distracting background. Avoid tiny lettering or logos inside the photo. This derivative has a different purpose from a press-kit master, which may need substantially more resolution.
Set dimensions rather than relying on appearance
Microsoft's small-business signature instructions describe inserting and resizing signature images. Use the controls available in your actual Outlook version and check both width and height so the face is not stretched.
As an editorial example, a portrait intended to display at 96 pixels wide could be prepared with a 192-pixel-wide source candidate for a higher-density screen. Those numbers are a starting proof choice, not a Microsoft requirement or a universal email specification. Compare a real received message before deciding that extra pixels help.
Worked example: an invented consultant signature
This fictional consultant originally inserts a large headshot and shrinks it visually in the editor. A forwarded message later displays it much larger than intended. The consultant creates a separate signature crop, sets a clear display size and places the name and phone number beside it as text.
Their proof compares three states: a new message, a reply and a forwarded message. For each, they record image scale, readable contact details and whether the surrounding layout remains comfortable. This is a suggested test method, not a claim that a particular export eliminates every rendering difference.
Keep the layout simple
Microsoft's photo-signature guide describes organizing an image and links in a signature block. Use restrained spacing and verify any table-based arrangement in the received message. Long titles, oversized banners and many icon links increase the number of things that can wrap awkwardly on a phone.
If the portrait is linked to a website, check the destination independently. A recognizable face does not make a broken hyperlink usable. Avoid placing all contact information inside one image that disappears when pictures are disabled.
Be precise about attachments and acceptance
An inline image can still appear in a recipient client's attachment interface. Do not promise that a particular signature recipe will produce zero visible attachments everywhere. The practical acceptance target is a modestly sized portrait, readable text and a message that remains usable without images.
Use Image Prompt if the portrait needs an approved visual revision, then create the signature derivative and configure Outlook externally. Keep the full headshot separate. Deliver the signature image with its intended display size and the results of the actual send test rather than only a screenshot of the signature editor.