I’ve used a trick for this a few times:
- You load the photos together with the GPX file in JOSM.
- Convert the GPX to a data layer.
- The photos are now right above the nodes of the converted track.
- Find a photo you want to correct the location of.
- Move the node under it and split the way at this node using [P].
- Find another photo to correct, move its node and split the way.
- Divide the nodes on the way between the two photos/splits evenly with [shift-B] (of course this only works on straight roads)
- Use any of the tools JOSM provides on the pieces of track you create.
- Now combine everything into one track again using [Ctrl-A] and [C]. (this one is important not to forget)
- Convert the data layer back into GPX.
- Align photos with GPX.
When you move the nodes with [shift-B] it’s hard to see what the corresponding photo of a node is. So it might be easier to repeat the hole process (a few times) then to try to get it right the first time.
Another useful thing I did was change the key bindings of previous/next photo to [Shift-;] and [Shift-']. This way You can hold the shift and move trough the photos with your left hand and use your right hand to (shift)click the photos to the correct location. This makes correcting geo-data of photos one by one twice as fast as with the original JOSM settings