you should go ahead and use dropbox. its free for 2 years and gives you 25GB of storage.
you can also use photobucket. it is a free app that uploads photos to your own photobucket account you set up.
so your internal storage is fine. seems you have the files there.
with ES file explorer,
navigate to /sdcard/DCIM. you should see your images there. of you may have a "pictures" folder*also. try there.
but yes DO NOT TAKE MORE photos unless you use Dropbox, photobucket or some other upload service app.