There are four-year-olds with better drawing skills than me. Thankfully, there is the Open Icon Library project to take care of all my icon needs. It is full of useful icons, indicators, alerts, flags, etc… The images are professional and polished looking, and there are a number of available themes.
Total icons: 137,396
Unique icons: 10,787
Unique PNG: 10,489
Unique SVG: 3,723
Everything has been pre-saved in a variety of formats and sizes, making it easy to grab art and get it working with minimal fuss. Even though this is an ‘Open’ project, the licenses vary per icon! Be careful of this on commercial projects. From the footer of the site:
“All icons are under free/open licenses, however the licenses vary from image to image. Some are Creative Commons, some are GPL, some are Public Domain. Licenses for sources app-install, wiki_commons-BSD, wiki_commons-CC,wiki_commons-GPL, , wiki_commons-MIT, and wiki_commons-PD”
Aside from license pitfalls that might come up, one limitation is the inability to search.
Sometimes a picture is also handy to pull into a project. In today’s world there are ways of searching only open source images. For example, the Flickr API supports searching for Creative Commons licensed images. Many other photo upload sites and content aggregators have jumped on open source bandwagon.
Again, you are dealing with a hodgepodge of licenses. What I have noticed is, creative commons licensed content increasingly becoming a high quality source of media. Enjoy!