I will show two methods that do not require to alter the files in the media library.
Accessing data from another user
Create a new (non administrative) user
otheruser, add it to your group:
sudo gpasswd -a otheruser $USER
Modify your home to grant read and execute permissions for the group members (this is required if you have an encrypted home partition):
chmod g+rx $HOME
Then switch to
otheruser, that should have now read access to all your data.
I should point out that, if you have an encrypted home partition, the other user could access your data as long as you are logged in. So you should login then switch user without loggin out from the first user.
Pretend to modify permissions
bindfs allow to mount a given directory with altered permissions, so the steps could be:
Install the package
sudo apt-get install bindfs
Create a mount point and assign it to your user
sudo mkdir /media/home-altered
sudo chown $USER:$USER /media/home-altered
Mount the real home to the mount point without write permissions:
sudo bindfs -p a-w $HOME /media/home-altered
/media/home-altered you will see your home directory with altered permissions, and accessing data through that path prevent to modify the data.
Almost the same effect of the second method can be obtained with a bind mount and a read-only remount:
sudo mkdir /media/$USER
sudo mount --bind /home/$USER /media/$USER
sudo mount -o remount,ro /media/$USER