Should I put pictures into a database?

I have an application, where I use pictures. The size of the picture is about 90kB and to speed up the preview, I made a thumbnail of each picture which is about 2.5 to 5kB. I use now a directory structure of ../$a/$b/$c/<pictures> I wonder if it would be good to put the thumbnails into the current table, in a different table or leave it like it is now. Same for the pictures. What is your opinion and why? bye Ronald