In addition to using test images, we also use photos to check the effect of filters in the real world. We generally use photos from Unsplash as our test samples, but you can also build your own test set. In general, a good test set should cover a wide range of colors and genres. However, depending on the filter and intention of the creator, the colors and genres of the photos in the set could also have a consistent manner.
Here are links to some images we’ve found quite helpful in our testing process.
https://unsplash.com/photos/UP5oOU9Gjg4
https://unsplash.com/photos/tYnnY7gKyZs
https://unsplash.com/photos/Hrt1sZGGh4c
https://unsplash.com/photos/jbtfM0XBeRc
https://unsplash.com/photos/y0SMHt74yqc
https://unsplash.com/photos/kufLAiPoIlI
https://unsplash.com/photos/iXmTYBLM4qg
https://unsplash.com/photos/rsE-ucjf_NU
https://unsplash.com/photos/08b-Ye5vDn4
https://unsplash.com/photos/N6MQK3Nx2X4
https://unsplash.com/photos/r2L6vCKaVRk
https://unsplash.com/photos/4UMUa1_BBig
https://unsplash.com/photos/guyW6IZKAGQ
https://unsplash.com/photos/nClgfxJoZ_c