I sometimes use Foter.com for images. All you have to do on their website is type in the scene or object that you are looking for, once the images have loaded, select commercial or non-commercial usage, located at the top of the screen. The page will reload and only show images that you may publicly use on your blog or articles.
If you wish to edit your images, you must click on the image and check the usage rights, towards the bottom right of the image. If the modification box is highlighted green, you can modify the image with a photo editor, if it states non-commercial, you must avoid using the image on articles.
Once you have saved the image to your computer, you must always copy and paste the owners photo credit details, printed at the bottom of the image screen and put them in the image attribution box, located on the upload photo area of your article.
Never use images that state not for commercial use, the owner can search their image using various programs and if they find you've used it without permission, they can sue you.
I hope that helps, I'm slightly rubbish at giving instructions and directions :) x