Personally, I don't think I need to choose my own photos to make a color-changing cup. Unless you have very effective photos and you are very satisfied with them, you should choose some pictures that have the meaning you want to express online. In fact, some pictures on the internet are exquisite and ingenious, and the effect is better.

I just make color-changing cups, and customers often take headshots and take photos with their mobile phones. No matter how beautiful, the effect is still very poor. If you must use personal photos, the best effect is to take them in a professional photo studio.