Windows Explorer keeps grinding down to molasses speed?!

Running ONLY Windows Explorer on Win98FE

Scenario: I'm looking for a specific group of several pictures. I
have 50 folders with 01.jpg throu 09.jpg in each. Since it is not
possible to search by name, only pictorial content, I go to each
folder and look at the first two or three to see if this is where
they're at. Ok, so far.

After each folder, Windows Explorer keeps getting slower. Refresh
doesn't help. Closing WE and reopening doesn't help, only rebooting
takes WE back to the original speeds.

To get through this process, I keep limping along, until WE takes over
20 seconds to list the 11 files in a folder!! Then I reboot and we're
back to zip, zip. until after looking thru a few folders and I'm back
to 20-30 seconds to list the contents.

What's happening here? Is there any way to 'refresh' the situation
without having to do a reboot?