There are two main steps in the process of uploading an image to your email signature in Gmail.
Step 1. You will need to acquire an image url
- Go to http://imgur.com/
- Click the upload images button on the very top left hand corner of the screen
- Drag and drop your image onto the screen
- Click the start upload button
- Once it is uploaded copy the url under "Direct Link (Email & IM) on the right hand side of the page.
Step 2. Upload the url to your Gmail email signature
- Go to your gmail settings
- Scroll down to your email signature and press the insert image button
- Select Web Address (URL) from the menu in the popup menu
- Paste the image url you copied from imgur.com