If you are uploading a photo from a website or Google Images, you simply click it (If it doesn't do anything when clicked, just continue), than right click and press Properties (If you're using Chrome, just press Copy Image URL). In the Properties, you'll see the image url. Copy that. Then go to the part of the post you want to put the image, click the "image button" and paste the image url. If you have a saved picture on your computer, either email it to yourself or upload it on Photobucket and do the same process. (:
like that i hope