Many images and photos found on the internet can be reused on your blog if they carry a creative commons license. In short, creative commons licenses protect the owner of the original licensed work without applying a full copyright, meaning others can use it (with possible restrictions).
You'll need to read the restrictions related to each photo with a creative commons license to understand how you can use it and what attributions or other requirements you need to meet to legally use it. There are six types of creative commons licenses described below.
This is the most restrictive creative commons license. This type of license allows you to use the image or photo but you may not alter it in any way and you must mention the owner and link back to him or her.
This license allows you to alter or build upon the originally licensed photo or image for non-commercial purposes, but you must credit the original licensor and license your new work under the identical terms of the originally licensed photo or image.
With this license, you may edit or build upon the original photo or image non-commercially. You must acknowledge the original licensor, but you do not have to obtain an identical creative commons license for your work.
You may use a photo or image with the attribution no derivatives license commercially or non-commercially, but you may not edit it in any way and you must credit the source.
You may alter or build upon a photo or image with the attribution share alike license for commercial purposes but you must give credit to the original licensor and license your new work under the identical terms of the originally licensed photo or image.
This is the most open and flexible creative commons license. If a photo or image has the attribution creative commons license, you may edit it and use it commercially as long as you credit the original licensor.
You can learn more about creative commons licenses or obtain your own creative commons license for your blog's content on the Creative Commons website.

