>What does the (u) and (h) mean next to a picture?
(u) downloads the file with the name that was originally provided by the first person who uploaded that file.
(h) downloads the file with the name used by the 8kun system (the SHA-256 hash of the file content).
These two links provide the exact same file (the full image posted to the board) but with a different name.
>Where can I find pic from old breads?
>Was 8kun designed to loose the pics on purpose and why?
Yes this is by design, to save server space I guess? There's a component of 8chan/8kun called "alacrity" that is responsible for purging old data, it used to be mentioned in the 8chan faq page but I can't find any specific info now.
What pics are you looking for? There are a few anons that keep automated archives of just about everything, including me.