Please do not email large files.
Often the quickest way for us to look int oa problem is to recreate it. So, if you are able, please zip and send your open InDesign files along with any relevant other files (e.g. audio files, EPUB or PDF) to us via wetransfer.com use the email firstname.lastname@example.org for reference.
Alternatively if you are a Dropbox user please use this link.
Packaging the fonts is always helpful if you are able to do so but typically we don't require large image links unless we have asked for them.
If your files are over 2GB then transferbigfiles.com is a good alternative.