Two excellent image sources are Pexels and Britannica ImageQuest.
Pexels is a free re-use image cite. Users technically do not have to cite the image but it is respectful to give the creator credit. The IB will require an image citation and reference. Access the tutorial below for step by step instructions.
ImageQuest is a subscription database of millions of rights cleared images (for education use only). Access the tutorial below to see how to filter specific photo collections and use CiteFast to generate the necessary reference.