How did I use 1.3 gigs of data by taking pics? Not sending them, just taking them!
When you say "use 1.3 gigs" are you referring to your data usage? Just making sure your not referrring to your device storage. You can easily use 1.3 GBs of storage on a device simply by taking pics.
In terms of data usage Ann154 is onto something. Generally speaking, Google Photos is set to only backup via Wi-Fi. But things to check are:
Applications (apps) setup to auto update etc. can cause cellular data depending on settings. Def look at what has access to use your cellular data via the settings.
Did you have the Google Photos allowed to upload to the cloud over cellular data?