7. [ ] `sxiv-exclude-strings` does not work recursively, because only the directories are passed to the process. Adding all files to the path might cause it to fail (bash length limit), or take a long time.
9. [ ] Bug - sometimes, if a lot of files (usually over 50) are marked in sxiv, the input received by `sxiv-insert-subdirs` is incomplete - the first file name is a trailing segment of an actual existing filename, e.g. if a file is called `"foo/bar_baz.jpg"`, I might get something like `"r_baz.jpg"` as the first element.
10. [ ] Optimize startup speed, especially with a large number of files.