what do i do if i want the pictures off of my old phone but i forgot the passcode

Since you don't remember the passcode, you will need to follow these instructions to get into the phone...

https://support.apple.com/en-us/HT204306

The process will ease the phone. I see no way for you to get the pictures from the phone unless you have backed them up to another device. Or they have been imported into Photos on your computer.

You can't, you need to remember the passcode. If you try too many times and it disables the phone, they will be gone forever so be careful with too many wrong attempts.