Feature Request/Idea: Improve alt text for image files in datasets

Overview of the Feature Request
When a dataset's image file is displayed, it might improve accessibility if its alt text is more descriptive.

As of Dataverse v5.9, image files in datasets are displayed as thumbnails on several pages, including in the search cards on search pages and in the "Files" tab on dataset pages, and the alt text for those image displays seem to be either the dataset title or the name of the image file, depending on where the thumbnail appears.

When the image is displayed on the File page in the "Metadata" tab, the alt text is the name of the image file. When it's displayed on the "Preview" tab by the Previewers tool, the alt text is an empty string.

What kind of user is the feature intended for?
(Example users roles: API User, Curator, Depositor, Guest, Superuser, Sysadmin)
Curator, Depositor, Guest

What inspired the request?
A depositor recently emailed a repository to ask how they could include a description of their images that can be used for the alt text.

What existing behavior do you want changed?
When the images in datasets are displayed, e.g. in thumbnails and on the file pages, the value for the alt text attribute can be something that the dataset depositor or a curator can define instead of using the file's name or the dataset title.

Any brand new behavior do you want to add to Dataverse?
Allowing the depositor or curator to define the alt text might be done by adding a field at the file level for entering alt text or using what's entered in the file's Description field.

Any related open or closed issues to this feature request?

• https://github.com/IQSS/dataverse/issues/6106 was about adding or improving alt text for the images in the application, such as images that the UI uses

Start by reviewing the image displays in search cards, the dataset Files tab, the File page Metadata tab, and the Previewers tool's Preview tab. Determine how a depositor or curator could define alt text, then verify that the chosen value is used consistently for the listed image displays.