Support thumbnails in attachments

[walldenfilippa]

Description

Description

In the app-frontend-react repository I want to add a thumbnail file of the attachment in the attachment component. However, there will be a need to display up to and maybe more than 100 images in the attachment component. At the moment, backend is not supporting thumbnails(reduced files sizes) which means that we can only download full size images in the frontend repository. The support of thumbnails in the app-lib-dotnet is therefore necessary for this feature, if we have a number of files to display.

The use case

Additional Information

Slack discussion link

https://altinndevops.slack.com/archives/C045EB3JA9X/p1714461684302109

[ivarne]

With 8.5 there will be an opportunity to utilise the new IDataWriteProcessor interface where you can watch uploads and deletes of a specific data type and add the thumbnail in a different data type.