Do you know that you can you can actually create image email signature on your iPhone and iPad? It’s pretty simple. First you will need a server to host your logo image. With any available FTP software, upload your logo image to your server and joint down the absolute image path E.g. http://www.mywebsite.com/email-signature.jpg.
Next, download a free app, Nitro HTML from the App Store. Create a New Page and enter the HTML codes for your image (IMG tag and absolute path) follow by your company name. You can insert HTML such as bold or italic to style your company name.
Copy the HTML codes and paste it under your email signature account under Settings->Mail, Contacts, Calendars->Signature. That’s it. Note that you can create different signatures for different email accounts.