How do I use cheat engine to change a value I don't know the number for?

I have cheat engine 5.5 and I am playing a game where I want to change the value of something. That something I want to change the value of is not based on numbers, but pictures (like dogs and fruit and stuff). I don't know the value of these. How can I find out what they are and change them?How do I use cheat engine to change a value I don't know the number for?Looks like you're going to have to find the value of pictures.How do I use cheat engine to change a value I don't know the number for?u shud be banne 4 hacking