If you are running iOS 11 or above on your iOS device, your photos may be saved as HEIC files. However, this format isn't compatible with all other services just yet.
For example, if you are using the Automatically back up your new iOS photos to Google Drive Applet, it will fail if your images are in HEIC format. You will need to switch to saving images as JPEGs for the Applet to successfully run.
Here's a useful article that walks through the process of making this change so that you can continue using iOS Photos Applets without problems.