I added this to Port Request on GitHub, but I'm hoping people who want this will add to it, or perhaps someone who can port will have a look at it. 🙏
https://www.drupal.org/project/imce_filefield
Backdrop already has IMCE ported. This add-on module allows linking to multiple existing files at once in the file field, not just through the WYSIWYG editor. (This functionality has been included in Drupal IMCE 8).
HOW IT WORKS
If you've got an events-orientated site with photo galleries, this is the module you need. I use it on every Drupal website. It allows you to link to 100 photos in a single action, PLUS keep your photo's tidy in subfolders.
IMCE File browser has lots of other useful functions for identifying and compressing large images.
1) I create a sub-folder and FTP all the photos. (That sounds like a hassle, but it's easier than fiddling with filefield paths, especially if you often delete old galleries.) You can upload files using the IMCE file browser interface if you're just doing a few.
2) On the file field, click "Open File Browser", highlight all the files and click Select.
3) All the files are attached.
I don't know what it does in Manage Files, but I hope it is the same as any other method.
Comments
@diannevolek , wondering if you have tried File Field Sources, which seems similar to what you are describing?
I am currently using Field Field Sources, but it doesn't work efficiently with "bulk files".
1) You can only add one file at a time, then wait, then add one more file. IMCE filefield allows you to select any number of files already in the File Browser (I've done galleries of 100s of files) and when you click select, all the files come in at once. You don't have to remember what you've already done.
2) File field Sources "transliterates" file names. I need my file names to remain capitalized for usability once downloaded, and identical to my master originals.
3) Field field Sources duplicates the files (due to transliteration?). I have two of everything. Possibly each time I attach the file to different content, it might be making more duplicates. When some files go up to 30MB, this is a problem. It will be a maintenance headache when files need to be replaced. I already don't know which file is actually being used.
4) There is currently a Token error, so you have to save the entire "page" each time you add one file.
5) I'm not sure what is happening under Manage files. Some of my uploads are there, some not. And files that I know are used more than once, are only showing single use. This means that if I use the Replace function for maintenance, perhaps only some files are being replaced? I won't ever know for sure without testing every download.
IMCE file browser has some useful functions, like compressing photos. Or finding massive photos that clients uploaded without realising it. It's a great module on it's own, but with only WYSIWYG, it's functionality is very limited.
IMCE Filefield extends IMCE to content type fields (file and image) and not just the WYSIWYG editor (with mobile, I never let clients upload images and files in the editor anyway)