Just a few random searches.
i want my weather & clock back on top of my htc blinkfeed
For this you need to set Blinkfeed as default start screen or it will act as “second screen” and not show weather & clock. For a guide on how it’s done, read THIS.
htc one m8 pictures keep saving in gallery
No, it doesn’t actually save anything TO the Gallery as that’s not a fixed place/folder on the android phones. What’s happening is “simply” that that Gallery app includes folders to show in it. Sometimes folders you don’t want there, the solution is rather simple tho. Read how HERE.
clear cache partition htc one m8
I assume M8 running Lollipop, since it differs a bit from how it’s done in 4.4.x. But, you have a guide on it HERE.