Most Android smartphones now, especially those in the flagship class, camera devices can already take photos in RAW format. It is a picture taken directly from the sensor without going through any post-processing.
This feature gives users the freedom to edit their own photos, such as setting color profiles according to their individual tastes. But, if the user is using Google Photos – this application will only back up and display the post-processed images. RAW photos are stored in foreign folders that are not displayed in Google Photos.
Later, the Google Photos application will start displaying RAW images. Although these images are not backed up to Google Photos, users can go to the application library and look at the Photos on device row section to directly access the RAW image folder. This allows users to share, back up manually or even edit directly from Google Photos.
For now, if the device supports RAW mode – Google Photos will display an icon that looks like a camera lens to make it easier for users. While on the device's album application the RAW label will be clearly visible. But my advice, if this feature has been rolled out and distributed to all – don't backup the RAW folder because the image size is very large and can consume the storage quota very quickly.