As it is well known that Pictures worth thousand of words and there is no defying from this fact. This is due to face that our brain have 2 parts one left and one right. One part of a brain is very master is understanding pictures rather than text, and that very part is hammered time and again and again. Lets come to the point…
You can find Images from Google that no big Issue , you can find them and use them as needed. The problem is when you will be famous then even one issue against will be hammering you, so better to take care right of them right now. Why to make a issue of these. Mind you now a picture and licensed and copywriter, and if you use any of these picture which are in such a form in that case, you may be penalized with by the original owner of the pictures. This is really a good one though to have blog of pictures and earn for the same.
The first help for blogger for the pictures is Stock Exchange the link for the website is below http://www.sxc.hu. Just go there search the picture over there, all the picture are free to use with some general license that you will not promote unlawful content. Take time to go through the license for where not to use, That all you are normally free to use in your blog.
The next help for the blogger is Flickr from Yahoo the web site is FLICKER , but there are many category which are not free to use commercially. Please do check the same hear . They have the license called creative commons which take care of the use of their picture .
So now the resources is in your hand use it as you wish. >