Many folks use WordPress to manager their blog. It is a powerful content management system that saves you time managing your articles, photos, videos, and other material. Many bloggers include photos that they have not taken themselves on their sites. There is nothing wrong with that as long as proper attribution is given and the original producers do not mind people sharing their work.
You could always add new photos to your website by downloading them from the original source and uploading the resulting file manually to your site. Remote Images Grabber is a cool plugin that saves you a step in the middle.
Once you install this plugin, you can access it from the Media section. Just enter the URLs of the images that you want to upload to your site, and this script takes care of the rest for you. Want to attach images to a certain post? Grab its ID and feed it to this plugin. You do have the option to define a file size limit or ignore files that are too small.
Before using this plugin, you want to make sure you have the right to add the images that you have found to your website. Remote Images Grabber can save you a lot of time grabbing images from the Internet and saving them to your website though.