This trick didn't work for me. So, I did what the system should have done with the .nomedia file present. I moved all of my photos to a hidden folder (with a . before the name) and removed the DCIM folder. Then, I looked for all instances of the .nomedia file (Root Explorer helped) and deleted them. Rebooted the phone. Started Gallery. Waited for 10 minutes. Voila! Gallery showed every little image file that was on /sdcard. To remove the files that I didn't want to see, I copied the .nomedia file from a random system folder and pasted it into all the folders that I didn't want indexed. Strangely though, moving even one of the original /sdcard/DCIM/Camera files from the hidden folder into the current Camera folder took Gallery down. Stranger that this also made the Internal Storage show a blank window when I connected the phone to my laptop. Almost positive that this has to do with JellyBean creating a /storage/sdcard0 folder that's linked to the older /sdcard folder. Looking it up and will post updates if I find any.
Update: The same trick works for Paranoid Android's JellyBean ROMs (even the latest 2.13) for the Galaxy Nexus. Something to do with the DCIM folder and how it is handled by Media Storage. A Linux-geek friend of mine confirms this has to do with the /sdcard0 symlinking. Although, why we need something like that is beyond my limited knowledge of the OS.