Why aren’t any picture markers showing up on the map after I’ve uploaded my pictures?
Two possible reasons for this: Either the GPX file you’ve uploaded doesn’t contain time information, or the time stamp of your photos is missing. Both these are needed for the time-based geotagging to work, and to allow marking of the picture’s location on the map by means of the camera icon. Some photo manipulation software may remove the time info (EXIF metadata) from the pictures, so that would be something to look into. And some GPS units may strip time info from their saved tracks to save memory. Either way, your pictures will still be represented in the thumbnail gallery below the map.