* lisp/image/exif.el (exif--direct-ascii-value): New function
(bug#40127).
(exif--parse-directory): Use it to get the correct values for
in-directory (i.e., shorter than 4 octets) strings.
This is in preparation to doing further work in this area to avoid
regressions.
* test/data/image/blank-200x100.png: New file for testing
image scaling.
* test/manual/image-size-tests.el: New file.