There are many places online to find free images to use for projects. Even Google has a search feature to narrow results to free usage.
Pixabay - my go-to choice; contribute your own
Pexels - Free photos with CC0 license; contribute your own
UnSplash - Free photos with CC0 license; attribution appreciated; citation provided
ISO Republic - CC0 licensed photos
Gratisography - quirky photos with CC0 license
Negative Space - Free photos with CC0 license
Life of Pix - Free high resolution photos
FancyCrave - Free photos; attribution appreciated
Free Digital Photos - must attribute creator
SplitShire - 997 free photos for commercial use
StockSnap.io - beautiful free stock photos (check out the food pics!)
Creative Commons Search - find images labeled with CC licenses