Limit file upload types

I am trying to create a folder to limit a class/group of users to only upload photos (for purposes of this post I’ll simplify this and just say jpeg files). I am running version 19.0.3 of Next Cloud and all associated apps are up to date.

I am working with a group of individuals who create publishing projects and the normal sharing settings for folders works for them. My problem is with a small group of people that act as photographers. I want to limit them to a single folder, and only allow them to upload jpeg files in that folder. I’ve tried using the File Access Control app, but it doesn’t seem to work for individual folders. I’ll explain what I’ve tried using a simplified example of my NextCloud site.

My folder structure looks like this
Project A
Project B
Project C
Images

here’s my Groups:
Group A
Group B
Group C
Photographers

All folders have been shared with all the different groups (A, B, and C) and they all have editing, creating, and deleting privileges on all folders including the Images folder. The Images folder has also been shared with the Photographers group and they only have “create” privilege on that folder (I don’t want them to delete any other Photographers upload to the folder).

I’ve been trying to find a way to limit the Images folder to allow Photographers the ability to upload only MIME files types of “image/jpeg.” I don’t want them uploading anything but images. Here’s what I’ve tried:

Step 1. Create an invisible tag called “images-only”
Step 2. Create a “Block access to a file” flow as shown below.
When File is Accessed:
Files System is tagged with images-only
File MIME type is not Custom MIME type of image/jpeg
Step 3: Tag the Images folder with that tag.

Now, here’s the interesting part. If you are in the Images folder when you perform step 3, the process works perfectly; you can only upload jpeg type files. However, when you try to get into the folder from the top level, access is denied by the rule and you cannot even get into the directory (i.e. the rule itself blocks access to the folder).

I don’t want to deny the upload of image/jpeg type files for the whole site, just that one folder and for that one group. I have not seen any real solutions out there after searching for several days and though I would throw something out here to get some new ideas. Thanks for reading…