Are you wondering whether it’s worth the trouble to add photo images to your author blog posts? You don’t have to wonder any more. The results are in. A recent study by Skyword revealed that a relevant photograph or infographic added to a published article increased total views by 94%.

Have you noticed how shared photos on Facebook receive a lot more comments and likes than just a text status update?

With that kind of information in your back pocket it’s a total no-brainer that adding images is a “must do” task for any blog post you write.

Here’s a list of free great photo resources.

9 Free Photo Image Sites

Morguefile.com: “The morgue file contains free high resolution digital stock photographs and reference images for either corporate or public use.” Plus, you “are allowed to copy, distribute, transmit the work and to adapt the work. Attribution is not required. You are prohibited from using this work in a stand alone manner.” It doesn’t get much better than this.

Foter.com: Great site. Lots of images. You are asked to give photo credit for each picture used and they provide an easy link to do so.

Stock.xchng: Lots of images of high quality. The images are free to use on websites but you must get permission from the photographer for print or commercial use. Must register with site to download images.

FreerangeStock.com: Must register with site. Lots of great photos. The top row of photos on each page are from Shutterstock and are not free, so watch out for that. You can use the free photos for commercial use.

ImageAfter.com: Not a lot of “great” professional-type images. To me they seemed to be more of the home photo variety but that will work just great some blog posts. You’re allowed to modify the images for personal or commercial use and can even sell them if they’re part of a printed works such as a book cover, poster, etc. You don’t have to register or give credit.

RGPStock.com: Must register and asked to give credit to the photographer. Lots of great photos.

Stockfreeimages: Must register and provide author attribution and a link back to the site. Lots of good pictures, impressive variety. Images can be used and modified and can use up to 10,000 printed copies for free. The top row and bottom two rows of images on each page are not free so stay in the middle for the free ones.

BigFoto.com: Beautiful high-resolution photos of geographic areas/cities. Free for personal use but must provide a photo link to BigFoto with each image. Paid options available for commercial use. Not a lot of images.

StockPhotoForFree: Must register. Lots of photos but the images are taken from video clips so the resolution is not always sharp. One interesting feature is that you can search by categories.

If you still haven’t found your perfect free photo, this page has a list of 73 free photo sites that offer some interesting options: 2yi.net. Not all the sites are working and some take forever to open (a few never did) but you can explore sites from NASA, the National Forest Service, US Dept. of Agriculture and even a site dedicated totally to insect photos. Interesting.

Use these resources to spice up your author blog posts with great-looking images. However, you wouldn’t want to ruin your book cover with cheap images or unprofessional design. For truly professional-grade stock photography, such as images for the cover of your book you’re going to publish, it’s best to go with a more professional stock photography service such as ThinkStock or iStockPhoto.