Two great tools I use for capturing images and loading them on my site are:
Jing to capture pictures and Paint.net to resize the pictures.
Both are free applications. You can go to You Tube and find tutorials for both applications.
As said above left click, copy image as, save to a file. I put a file on my desktop labeled pictures.
When you get ready to upload to your hub, click choose and go to the Pictures file on your desk top. Select the picture you want to use and double click to upload. Make sure the tab is set to Upload.
Make sure the file is a GIF, JPG, or PNG only when you upload.
Hope this helps.