in /home/user/.cache/data/ folder: I have two folders inside twitter and twitter-meego. Twitter meego-folder contains only one file called twitter-cache.db and it's size is 1.29 mb, in "twitter" folder I have a lot of subfolders, with pictures I can't even open because they are damaged...

About .tumbnails folder, can I just delete all folders in this .tumbnail folder?

Can this affect the operation of the phone itself or other apps (maybe the contacts pictures)?

Just asking, because I've never done this before, and I want to be careful
Thanks.