Another source of images that is free is, of course, your own photos. The challenge can be cropping and resizing those photos once you have them on your computer. A camera image is often not cropped correctly or not rotated right, and is often very large.
You can use a free image editing tool like Google’s Picasa to adjust colour, brightness, crop and rotate then save for web.
While I will give you a quick tutorial here, I suggest you go to https://support.google.com/picasa and read all of their tutorials.
Picasa will scan your entire computer for photos and let you view them through the Picasa portal. All of your images will stay in the same folders they were originally in, this just lets you access them a different way than going through Windows Explorer.
When you have a photo you want to crop and adjust, you can simply right-click on it and select View and Edit.
You will see the photo in the main section and icons of the tools on the left.
Here I have selected Crop then Clicked and Dragged a selection by holding my left mouse button to choose the area to use. Next I click Apply and I can Save As a new image – again with a logical name and folder location.
Follow the steps in lesson 1 of this series to upload and insert into your WordPress Post.