Android 4.x - low memory: Delete folder Thumbnails properly and get a bit 'of space.

Who of us, when installing new updates to the app on your device Android, has never displayed the message "Update failed: insufficient storage available"?
The ever-increasing memory requirements by the app makes all desperate for space, and a general system cleaning is not enought (although still useful).  

It is often necessary to move photos, video and audio on the SD card or on your PC.
Sometimes, getting tired, we decide for rooting the phone, facing this operation and its potential risks.
Before coming to drastic solutions, if you have a device equipped with a version of Android 4.x, you can try to get rid of a folder that, for a known and widespread bug , grows ever more until reaching gigantic proportions.
In the phone, there is a folder named "DCMI" that is meant to store the images in a variety of programs (the camera by default, facebook, instantgram, etc). Inside this folder, however, there is another, hidden, in charge of the storage of thumbnails. Here, as well as many small pictures (which act as a preview for some applications), there are files with no extension, coming to a very large size.
The folder in question is called ".thumbnails" and simply deleting it is not enought.Following the advice found in a forum (the sources are indicated in the footer), I'll explain how to remedy the matter.

1. First of all, look in the app store for "ES file manager" and install it. It 'a great program for managing files on your device.
2. Open Es FIle Manager. In the upper right corner, just to the left of the "x", there is a box. Click on it and you get to the memory of your phone. To access it, because the nomenclatures may vary by phone to phone, you should click on the first partition visible just below the "/".
3. Open "DMCI" director.
4. Create a new file. For now, name it "NEW1".
5. Connect your phone to your PC. (You could also do this using the wireless and an FTP program like filezilla, via a convenient option for ES File Explorer ..).
6. Copy on your PC the directory named ".thumbnails".
7. Once copied on pc (this will be used for backup), delete the directory ".thumbnails" from your phone device.
8. Disconnect the phone from the PC and open again, using ES File Explorer, the folder "DMCI" on your phone. (I used an FTP program and I have unplugged the phone from the pc.)
9. Tap and hold the file created earlier, "NEW1", and select from options "rename". Rename it ".thumbnails." Remember the dot, before thumbnails. 
10. Reconnect  the phone to your pc. From there, open "DMCI" folder stored in your phone.
11. Right-click on the ".thumbnails" file and click on proprieties. Then put the check mark for "read only". In this way, the file will not grow. If you are using an FTP program, right-click on the file from ftp window, click on "Permissions" and uncheck "write".
12. Unplug your phone and reboot it.

This is the End!

Sources:


Androidiani.com
xda-developers.com