If the orange Camera light is solid and you are taking photos, but they are not registering as pics on the Reader:
You might not be saving the correct image format. Double check that you have a memory card in the camera and that you are saving JPEG images (Walker will only download JPEG files – not RAW). Double check your important camera settings.
If you have multiple Walkers, the Reader might be connected to a different Walker. Check that your Reader is paired to the right camera/Walker by disconnecting the current Reader and pairing again. Instructions here.
You might be in Scan First Shooting Mode. If you are in this mode and you try to take a photo before scanning an ID, the Reader will beep and display a trash can with the message "ID First" to tell you that the image was not accepted. Switch to Photo First Shooting Mode if that is how you want to work. See here for more info on Shooting Modes.
You might be in Sync on Scan Tether Mode. Is there a question mark instead of a number of pictures? If so, you should read more about Tether modes and select the right mode for you.
If it's still not working try: