Edit XML metadata

[lambdamoses]

Would it be possible to add a function to edit the XML metadata of the OME-TIFF file? Say for instance, I'm only keeping a lower resolution from a pyramid (to create a small example dataset for unit tests and examples in function documentation), which has different physical pixel size from the full resolution, so I need to edit the physical size field in the XML metadata. I have been using the xml2 package to edit the XML after reading it into R and then I used the tiffcomment command line tool to replace the XML metadata, but it would be nice to do that directly within R if possible.