Images from google image searches cannot be used without permission! You must obtain / buy proper license or usage permission rights from the original source (photographer, graphic artist, reseller agency, etc.).
I would not advise you to do that. It’s very bad idea! You know, many owners of pictures don’t want to give their pics just for free. If they found their pictures on your or other sites, they will send you a letter with their complains. I even don’t want to think what could happen in the end. Mostly, these pics are copywrited, so try to find good ones on the stock photos, free or paid. It’s the best solution.
Where are some good public domainish type of images? It’s hard to find good ones… Kinda makes you how the “copyrighted†ones got their images in the first place.
You have to check if the image/picture is copyrighted. If yes, you can use it unless you ask permission from the owner of that picture.
If it's copyrighted you have to either contact the owner or give a link and credit to the author when using it. On Flickr, it's really easy to do this as you can simply PM them and ask so try doing that first.
for a photo always get permission from the owner of the photo to use it... they may claim big $ from you otherwise...
It will create issue, as it was termed as copyright. But i think you may denote the owners name in courtesy, below the image after you use.
I individually use many picture from Google. Most of the photos from Google is copywrited the owner of that image may send you a demand letter. Besides, copyright picture you can use others from anywhere of the Google.
Using advance search, you can filter out non copyrighted images but still there will be a risk factor of unintentionally using the copyrighted images.