Images are not saved in your device gallery - the gallery just displays all the images that are on your phone, UNLESS they are in storage associated with particular application. Use the following method do determine where you should save the images.
private File getAbosoluteFile(String ralativePath, Context context) {
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
return new File(context.getExternalFilesDir(null), ralativePath);
} else {
return new File(context.getFilesDir(), ralativePath);
}
}
It will store them in external storage associated with your application and they will seize being displayed in the device's gallery. Try this out with new image, because images are cached for a long time in the gallery application.