The web uploader has just been updated, and you can now duplicate observations and drag to reorder observations.
To duplicate an observation (or observations), select it (or them) then click “Duplicate” at the top. Everything about the original observation will be duplicated except the species guess, observations fields, and projects.
To reorder a observation, drag and drop it either between two other observations or to the edge of another observation. You will see a dotted line appear, showing you where the observation will now be placed.
If you find any bugs, please file a bug report.