Do you confront your partner over Snapchat and her photos?

“I unlocked my girlfriend’s phone out of boredom while she was in the shower. I knew her passcode from seeing her unlock it before.
I opened her snapchat and noticed she had streaks going with people I’ve never heard of. In her photos, she had a bunch of lingerie pics that she’s never sent me.
Is this something I should be worried about, or could it be innocent?”