if i reset my phone because i dont know the password am i going to lose all my contacts and pictures ?

i locked myself out of my phone and i am unable to remember the password if i reset the phone am i going to loose all my pictures

Resetting the phone will cause you to lose everything on the phone. It will appear as if it did when it was brand new.

If you have a current backup of the phone, you can use that to restore the phone, so it will look just like it did before you forget the passcode.

If you don’t have a backup (either via iCloud or one done on a computer) then yes unfortunately you will lose your data

You will lose everything that was not backed up or synced to the cloud.

Yes