When I search filenames of images in Finder, using the box in the upper right corner, the result does not display the thumbnails, see attachment where I searched for 2015.
Otherwise the thumbnails display normally.
I have already deleted com.apple.finder.plist in Library/Preferences and relaunched Finder and in "Show View Options" Cmd ⌘ J the show icon preview box is ticked. In "Show View Options" I also modified the Icon Size, Grid Spacing and Text Size without success.
The images are associated to be opened by Preview in Get Info->Open with:. I do not have DropBox installed.
I am running MAC OS Mojave.
Do you have any other suggestion ?