Dynamics CRM does not allow you to paste graphics directly into an email in a workflow, e-mail template, or when you’re manually creating email activity.
You can however, paste a graphic into an email using a link to a graphic that is accessible on the public facing website.
- Create a special page on your website that contains all the graphics that you would like to include in CRM e-mails
- Display a page containing the graphic you want in Internet explorer
- Right-click the graphic that you want to insert in your email and choose the “copy” option
- Position the cursor in your CRM email form to where you’d like to place the graphics, and press Control-V to paste
- The graphic will now appear in your email form, template, or send email workflow activity
Note the use of the yellow “slugs” that insert dynamic values into the signature template
Source: Dynamics CRM Usability Blog