Currently there is no option to manually set a thumbnail for the slider preview in the sliders list. The preview image is automatically pulled from the first availabe slide background image. We are planning to include an option for this in the future but it's not possible yet.
I worked some sliders from your demo store.
but i don't know how to change thumbnail pics on front slider manage page.
Please let me know and still waiting other questions I asked before as well.
Sincerely yours
Hey Seong Jin,
We have already replied to your other tickets.
Currently there is no option to manually set a thumbnail for the slider preview in the sliders list. The preview image is automatically pulled from the first availabe slide background image. We are planning to include an option for this in the future but it's not possible yet.