Images have their own url, and images are displayed in web pages by embedding an image’s URL with some HTML code.
If I wanted to find a picture of a cat, and I typed it in Google, then I wouldn’t know for certain that those images have a creative commons license, and are available for reuse with citation of sources.
I recommend using either Wikimedia Commons, Flickr’s Creative Commons, or Photobucket Creative Commons. If you need a picture from a source other than these three, be sure to give credit to the source.
For example, I really like this picture of this cat: http://commons.wikimedia.org/wiki/Felis_silvestris_catus#mediaviewer/File:Tabby_Pfaffengrund.JPG
You can tell this is the Image URL, and not the website’s URL because it ends with an image file extension: JPG–others are PNG, TIFF, JPEG, etc.
It’s too big to put in a timeline display, so we can select a smaller size to link to:
Click the Download button (1) and then select a smaller version of the image (2). For this example I will choose Small.
Then click the link below the green box, that says “View in browser.”
This will open the image URL in a refreshed page. It will show the smaller version of your image, and the URL will have the adjusted size reflected in it.
Example small: http://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/Tabby_Pfaffengrund.JPG/193px-Tabby_Pfaffengrund.JPG
If you are linking to the image URL for your blog post you can click “Add Media” and then on the left there will be a menu to select your uploading options. Click “Insert from URL,” and then paste it into the box it provides you.
It will also allow you to change alignment, and add a caption like you normally would when uploading an image to the media library.