Tree frog stock photo© Paul Fleet/Bigstock

Earth Day is April 22. To provide some visual inspiration, we collected a few of Bigstock's many beautiful images related to the environment. Themes like alternative energy, ecology, global warming, climate change and conservation are popular searches on Bigstock, and our artists have contributed many images with green themes. Browse through our sampling here and view a Bigstock lightbox of Earth Day-related stock images.

Hands with plant © Francesco Ridolfi/Bigstock

Glacier stock photo © Konstantin Kalishko/Bigstock

Smokestack pollution © Igor Zhorov/Bigstock

Tree in glass enclosure cloche bell jar © Ali Ender Birer/Bigstock

Planting © Jasmin Merdan/Bigstock

Solar panels © Carlos Oliveras/Bigstock

CFL light bulb © Andrea Danti/Bigstock

Alternative fuel © Slavoljub Pantelic/Bigstock

Recycle © James Thew/Bigstock

Windmill © Rafa Irusta/Bigstock

Polar bear cubs © John Pitcher/Bigstock