I had a picture on my device and did a Nandroid backup and then flashed the device without transferring the picture. Can I get just the picture out? I try exploring the backup but it's just a bunch of files I don't recognize.
You probably search for the contents of your internal SD card (the
Pictures directory I assume).
Then you need to explore the
data backup. Inside there should be a
media directory (and then maybe a
0 directory). This should contain your internal SD card's content of your user. There you can explore all your data.
Small side note: Not all backup methods save this particular folder. It's generally very big and should be backed up independently. Last I would also recommend an external SD card (if applicable) to save important data on.