I don't like it how you add the images, and hope they come out joined properly. There should be a way to preview before uploading, and fix any mistakes it made when joining the images.

yup

Indeed.
We're working on it.

It would be nice if drag-and-drop could be used in manually arranging the uploaded photos.

I would also like to see an ability to preposition photos say over a layout plan.  A further extension would be some feedback on "broken linkages" so extra photos could be supplied to fill the gaps (would also help in educating me in a better structure for my originals.

The software should allow points on pictures to be able to be selected and noted as being the same in other pictures when the software cannot automatically detect overlap in them due to a lack in obvious detail.  This way some groups of pictures from the past could be saved when there is no longer access to the situation in which they were taken.

Maybe a way to manually point out corresponding points. My first synth has an 'orphan'. I had to look hard to figure out myself where it belongs, but there is a place for it.

I agree! it is definately necessary at the moment to be able to arrange the uploaded photos manually in the correct order. Just spent time uploading, syncing, wondering what happened, deleting, selecting, removing, selecting each picture individually in the correct order until I finally got 100% sinthy! Not intuitive at all.

Maybe a way to place groups of synths. Like when it makes a separate group for each room of your house you could position them next to each other manually.