If you restrict the file types which can be uploaded this also restricts the file types which can be linked.
This essentially renders the linking option useless to those who want to restrict what is uploaded.
We use SharePoint and other online locations to store our files and do not want to have to maintain documents within Promapp when those change but want our people to be able to upload screenshots within their processes to make the content more rich.
If we restrict our uploads to only image file types this restricts the ability to link other documents.
We would like this changed so that linking and uploading can be restricted separately.