In Gmail there is no insert/upload image option by default. Let me show you how to enable the option so you can upload and insert an image into the email or insert an image by providing url.
I will show you how to enable desktop notifications, so you will notice a new email, even if you are not in the window where you have your Gmail account open.
Gmail predicts which emails might be of high importance to you so it marks them as important with a yellow icon. If your inbox ends up full of so called important emails, this is how you disable this feature.
If you activated the new Inbox Tabs then after a while you find yourself not liking them that much and would like you old priority inbox back, this is what you need to do.
Gmail offers you a new way of organizing your emails in tabs. You have a tab for you personal conversations, a tab for social media related emails, promotional emails with offers and a couple of more tabs.
If you don't want Google to store your chat history and the Google chat history of the person you are chatting with, you can take the chat off the record and this is how you do that.