We love photos and as long as they were taken by a smartphone or your camera in good light you did not crop them too much then they should print well. Using filters can also affect the quality of your pictures as well as too dark shots.
Photos taken with your phone in good light should print well. For the best results, we strongly recommend that all photos be at least higher then 5 megapixel if you want to choose full page favourites in e.g. the large landscape book we recommend a resolution of 8 megapixel.
We also recommend you to avoid using pictures that are transferred via WhatsApp and other services.