The best sources for finding free heart images are stock photo sites such as 123RF, Free Digital Photos and PngImg. These sites offer images that have been uploaded by artists or photographers for free use by the public.
These types of sites can require membership or have rules about how the images may be used in commercial or personal use. Some of the sites might limit how many pictures can be downloaded per account each 24-hour period as well. If someone is considering using these pictures for commercial work, they should make sure they check the license or rules for each picture they use in their work to avoid any kind of legal issues that could arise.