Opening images through context menu: Images not in alphabetical order

[Ofnuts]

There are two problems here:

1. The explorer starts one Gimp instance for each file, instead of starting one Gimp instance and giving it all the files. Normally a new instance looks an already running one and passes it the file, but if everything is started at the same time, the simultaneous instances may not have the time to show the others that they will take care of things. 
   
2. It is likely that the explorer orders the files by their natural order from its point of view, which could be the ordering of file entries in the directory in the file system (that are, in a fresh directory, the order of creation, but will change over time due to renaming, and erasure and re-use of empty entries).
   

If the groups of files you edit are isolated in their own directories, it is quite easy to write a small .BAT that calls Gimp on them, first starting an instance without image, then sleeping for a second to let it initialize, and then calling Gimp with the files in order.