I was putting some wallpapers on my SD card and I noticed some folders that I didn't put on there. There is .htcnews...inside the folder looks to be little screen captures from news stories. Can these be deleted safely? Also there is one called .bookmark_thumb1 and there appears to be little screen captures from websites I have visited with my phone. Can/should these be deleted? What exactly is the purpose of this data? Are they kind of like "cookies?"