If you are interested in putting photos on your blog, you have to make sure you aren’t violating copyright.
Summarized here by Alex Wild (@myrmecos).
Here is a useful blog post showing you how you can find free photos on flickr….
….and the link to the flickr CC search site.
Unsplash (free, royalty free, no attribution needed)
Photopin.com allows you to search CC databases.
Tinyography (square photos shot with an iphone – good for instagram)
And a list of 43 other sites.
You can also use an app like Zoomy ($3.99) to find royalty-free stock photos.