"Images" or "Pictures" as a user term?

UX Writing question - which makes most sense to average app users: Images or Pictures as a user term?

Touchgram has a Picture Background on a page but I'm opening up the document type to be able to drag images from macOS as well as send from other apps.

Coming soon is building up a page with overlaying smaller images as icons, stickers etc. I naturally use the word Images but need to settle on what to use in user terms. Pictures kind of made more sense when the only sources were the Camera or Camera Roll.

Context: Touchgram is an iMessage app that allows you to build interactive messages with gesture recognition on one or many pages. It's meant for regular consumers, not design professionals, hence my caution over language.