There is subjectivity in this category of muktzah machmas chisaron kis. If one does not care about an item, even if others do, it does not fall under this category. The opposite is true as well.
Pictures on a wall are a matter of dispute and some (Chazon Ish) designate art as a muktzah machmas chisaron kis. If it is not an extremely valuable piece of art, one may rely on the opinion (Rav Moshe Feinsten) that does not consider it to be muktzah and can therefore be straightened or moved on Shabbos.