Is there a way to force user to take photo instead of uploading?

Because sometimes a photo may be used to prove something and you do not want the user to take several photos a single time with his camera and then upload those photos inside AppSheet other times.

If not possible, is there any way to be sure the uploaded photo was taken (not uploaded) in a specific date/time?

If you set the UX > Options > Allow image input from gallery as OFF, your user is not able to add the image from the gallery.