I used to use a Galaxy S7 for flying my mini, and now use an S10. I often copy the full res pictures/videos onto my phone using the card reader. It plugs directly into the USB slot on the phone and works a treat. Below is the reader I have - I'm sure the equivalent is available in the USA too. It has USB A, Mini and USB C connectors so plugs into all of my devices old and new.
Make sure it's an "OTG" card reader so your phone will see it as a USB memory stick.
