Size column with Everything can go wrong if the index isn't right. Rebuilding it might fix things. If you're using 1.5, try 1.4 as well, as that's the only version we've tested. (1.5 is still in alpha.)
Folder thumbnails, I found the thread and replied: Thumbnails on folders are pixelated - #7 by Leo
Image/Video thumbnails, if you mean No thumbnails on network drives - #7 by Leo did you send us the info I requested? I can check if you did. It may be under a pile of other things to investigate, since we only have one report and it's likely to be an issue with an external thumbnailer or codec something has installed. But I can take a look if we have that data.