Hello bridgit26, Did you check your Settings > Messages > iMessage enabled? Also check SMS/MMS enabled? And to send to an Android you need to have Settings > Cellular > Cellular Data enabled. You can receive from an Android if Cellular Data is off, but you won't receive any Pictures from an Android if Cellular data is off.
I myself normally turn off my Cellular Data and depend on Wi-Fi when at home to save on Cellular data charges, but when I leave the house I must turn Cellular data back on and if I need to communicate with an Android user I turn Cellular Data back on. Hope this helps