miniatures display

Hello,

I have a question. When working with my photo's I always use the
"miniatures" for display in the folders. I don't now how, but the aspects of
this had changed. The miniature pic's are displayed much smaller now, with
also more at one row than before. Does someone now how I can correct this?
(and I got the idea also the letters are smaller....)

I thank you in advance.

Mafa