As you have said, you haven’t found your JPEG images in the Android’s file manager or even in any photos application. Right? But I would like to say there is still a possibility to recover hidden files in Android mobile by using the ES File Explorer app. Yes, is an app which is available on the Google Play store and used to unhide the hidden files on different Android device. To do so, follow these steps:
• Just open the Play store app on your phone and install the ES File Explorer app.
• Then, slide the right menu & choose the Tools.
• Next, go down and choose the “Show hidden files” option.
• Now, enable it, and then you can see all your hidden files on your Android phone.
To know more: http://www.rescuedigitalmedia.com/how-to-recover-hidden-files-in-android